2007-2014 Microchip Technology Inc. DS30009907C-page 1

PIC24FJXXXGA1/GB1 FAMILIES

1.0 DEVICE OVERVIEWThis document defines the programming specificationfor the PIC24FJXXXGA1/GB1 families of 16-bitmicrocontroller devices. This programming specificationis required only for those developing programmingsupport for the PIC24FJXXXGA1/GB1 families.Customers using only one of these devices should usedevelopment tools that already provide support fordevice programming.

This specification includes programming specificationsfor the following devices:

2.0 PROGRAMMING OVERVIEW OF THE PIC24FJXXXGA1/GB1 FAMILIES

There are two methods of programming thePIC24FJXXXGA1/GB1 families of devices discussed inthis programming specification. They are:

• In-Circuit Serial Programming™ (ICSP™)• Enhanced In-Circuit Serial Programming

(Enhanced ICSP)

The ICSP programming method is the most directmethod to program the device; however, it is also theslower of the two methods. It provides native, low-levelprogramming capability to erase, program and verifythe chip.

The Enhanced In-Circuit Serial Programming(Enhanced ICSP) protocol uses a faster method thattakes advantage of the Programming Executive (PE),as illustrated in Figure 2-1. The Programming Execu-tive provides all the necessary functionality to erase,program and verify the chip through a small commandset. The command set allows the programmer toprogram the PIC24FJXXXGA1/GB1 devices withouthaving to deal with the low-level programmingprotocols of the chip.

FIGURE 2-1: PROGRAMMING SYSTEM OVERVIEW FOR ENHANCED ICSP™

This specification is divided into major sections thatdescribe the programming methods independently.Section 4.0 “Device Programming – EnhancedICSP” describes the Enhanced In-Circuit Serial Pro-gramming (Enhanced ICSP) method. Section 3.0“Device Programming – ICSP” describes the In-CircuitSerial Programming method.

• PIC24FJ256GA106 • PIC24FJ256GB106• PIC24FJ256GA108 • PIC24FJ256GB108• PIC24FJ256GA110 • PIC24FJ256GB110• PIC24FJ192GA106 • PIC24FJ192GB106• PIC24FJ192GA108 • PIC24FJ192GB108• PIC24FJ192GA110 • PIC24FJ192GB110• PIC24FJ128GA106 • PIC24FJ128GB106• PIC24FJ128GA108 • PIC24FJ128GB108• PIC24FJ128GA110 • PIC24FJ128GB110• PIC24FJ64GA106 • PIC24FJ64GB106• PIC24FJ64GA108 • PIC24FJ64GB108• PIC24FJ64GA110 • PIC24FJ64GB110

PIC24FJXXXGA1/GB1

Programmer ProgrammingExecutive

On-Chip Memory

PIC24FJXXXGA1/GB1 Families Flash Programming Specification

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 2 2007-2014 Microchip Technology Inc.

2.1 Power RequirementsAll devices in the PIC24FJXXXGA1/GB1 families aredual voltage supply designs: one supply for the coreand peripherals, and another for the I/O pins. A regula-tor is provided on-chip to alleviate the need for twoexternal voltage supplies.

All PIC24FJXXXGA1/GB1 devices power their coredigital logic at a nominal 2.5V. To simplify systemdesign, all devices in the PIC24FJXXXGA1/GB1 fami-lies incorporate an on-chip regulator that allows thedevice to run its core logic from VDD.

The regulator provides power to the core from the otherVDD pins. A low-ESR capacitor (such as tantalum) mustbe connected to the VDDCORE pin (Table 2-1 andFigure 2-2). This helps to maintain the stability of theregulator. The specifications for core voltage and capac-itance are listed in Section 7.0 “AC/DC Characteristicsand Timing Requirements”.

2.2 Program Memory Write/Erase Requirements

The Flash program memory on PIC24FJXXXGA1/GB1devices has a specific write/erase requirement thatmust be adhered to for proper device operation. Therule is that any given word in memory must not be writ-ten more than twice before erasing the page in which itis located. Thus, the easiest way to conform to this ruleis to write all the data in a programming block withinone write cycle. The programming methods specified inthis specification comply with this requirement.

2.3 Pin DiagramsThe pin diagrams for the PIC24FJXXXGA1/GB1 fami-lies are shown in the following figures. The pins that arerequired for programming are listed in Table 2-1 andare shown in bold letters in the figures. Refer to theappropriate device data sheet for complete pindescriptions.

2.3.1 PGCx AND PGDx PIN PAIRSAll of the devices in the PIC24FJXXXGA1/GB1 fam-ilies have three separate pairs of programming pins,labeled as PGEC1/PGED1, PGEC2/PGED2 andPGEC3/PGED3. Any one of these pin pairs may beused for device programming by either ICSP orEnhanced ICSP. Unlike voltage supply and groundpins, it is not necessary to connect all three pin pairs toprogram the device. However, the programmingmethod must use both pins of the same pair.

FIGURE 2-2: CONNECTIONS FOR THE ON-CHIP REGULATOR

Note: Writing to a location multiple times withouterasing is not recommended.

VDDENVREG

VDDCORE/VCAP

VSS

PIC24FJXXXGA1/GB1

CEFC

3.3V

Regulator Enabled (ENVREG tied to VDD):

(10 F typ)

Note 1: These are typical operating voltages. Refer to Section 7.0 “AC/DC Characteristics and Timing Requirements” for the full operating ranges of VDD and VDDCORE.

VDDENVREG

VDDCORE/VCAP

VSS

PIC24FJXXXGA1/GB13.3V(1)2.5V(1)

Regulator Disabled (ENVREG tied to ground):

VDDENVREG

VDDCORE/VCAP

VSS

PIC24FJXXXGA1/GB12.5V(1)

Regulator Disabled (VDD tied to VDDCORE):

2007-2014 Microchip Technology Inc. DS30009907C-page 3

PIC24FJXXXGA1/GB1 FAMILIES

TABLE 2-1: PIN DESCRIPTIONS (DURING PROGRAMMING)

FIGURE 2-3: PIN DIAGRAMS

Pin NameDuring Programming

Pin Name Pin Type Pin Description

MCLR MCLR P Programming EnableENVREG ENVREG I Enable for On-Chip Voltage RegulatorVDD and AVDD(1) VDD P Power SupplyVSS and AVSS(1) VSS P GroundVDDCORE VDDCORE P Regulated Power Supply for CorePGECx PGCx I Programming Pin Pairs 1, 2 and 3: Serial Clock PGEDx PGDX I/O Programming Pin Pairs 1, 2 and 3: Serial Data Legend: I = Input, O = Output, P = PowerNote 1: All power supply and ground pins must be connected, including analog supplies (AVDD) and ground

(AVSS).

2345678910111213141516

4847

22

44

24 25 26 27 28 29 30 31 32

PIC24FJXXXGA106

1

4645

23

4342414039

RD

6R

D5

RD

4R

D3

RD

2R

D1

RE

4R

E3

RE

2R

E1

RF0

VCA

P/VD

DC

OR

E

RC13RD0

RD9RD8

RC15RC12VDDRG2

RF6RF2RF3

RG3

AVD

D

RB

8R

B9

RB

10R

B11

V DD

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/CN

25/R

B7

RF5

RF4

RE5RE6RE7RG6

VDDPGEC3/AN5/RP18/C1INA/CN7/RB5PGED3/AN4/RP28/C1INB/CN6/RB4

RB3RB2

RG7RG8

PGEC1/AN1/RP1/VREF-/CN3/RB1PGED1/AN0/RP0/PMA6/VREF+/

RG9MCLR

RB

12R

B13

RB

14R

B15

RE

0R

F1

RD

7

VSS

VSS

VSS

ENVR

EG

63 62 61 5960 58 57 56 5455 53 52 51 4950

3837

34

3635

33

17 19 20 2118

AVSS

64

RC14

CN2/RB0

RD10RD11

64-Pin TQFP

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 4 2007-2014 Microchip Technology Inc.

FIGURE 2-4: PIN DIAGRAMS (CONTINUED)

80 79 78

20

23456789101112

1314

1516

6059

26

56

403928 29 30 31 32 33 34 35 36 37 38

PIC24FJXXXGA108

171819

1

7677

5857

27

5554535251

RD

5R

D4

RD

13R

D12

RD

3R

D2

RD

1

RE

2R

E1

RE

0R

G0

RE

4R

E3

RF0

VCA

P/VD

DC

OR

E

RC13RD0

RD9RD8RA15RA14

RC15RC12VDDRG2

RF6RF7RF8

RG3

RF2RF3

RA

10R

A9

AVD

D

RB

8R

B9

RB

10R

B11

VDD

RD

14R

D15

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/CN

25/R

B7

RF5

RF4

RE5RE6RE7RC1RC3RG6

VDDCN66/RE8CN67/RE9

PGEC3/AN5/RP18/PGED3/AN4/RP28/

RB3RB2

RG7RG8

PGEC1/AN1/RP1/CN3/RB1PGED1/AN0/RP0/CN2/RB0

RG9MCLR

RB

12R

B13

RB

14R

B15

RG

1R

F1

RD

7R

D6

VSSVS

S

VSSEN

VREG

75 74 73 7172 70 69 68 6667 65 64 63 6162

5049

46

4847

4544434241

21 23 24 2522

AVSS

C1INA/CN7/RB5C1INB/CN6/RB4

RC14

RD10RD11

80-Pin TQFP

2007-2014 Microchip Technology Inc. DS30009907C-page 5

PIC24FJXXXGA1/GB1 FAMILIES

FIGURE 2-5: PIN DIAGRAMS (CONTINUED)

100-Pin TQFP

9294 93 91 90 89 88 87 86 85 84 83 82 81 80 79 78

20

2345678910111213141516

65646362616059

26

56

4544434241403928 29 30 31 32 33 34 35 36 37 38

PIC24FJXXXGA110

171819

2122

95

1

7677

72717069686766

757473

5857

2423

25

9698 979927 46 47 48 49 50

5554535251

100

RD

5R

D4

RD

13R

D12

RD

3R

D2

RD

1

RA

7R

A6

RE

2R

G13

RG

12R

G14

RE

1R

E0

RG

0

RE

4R

E3

RF0 VC

AP/

VDD

CO

RE

RC13RD0

RD9RD8RA15RA14

RC15RC12VDD

RG2

RF6RF7RF8

RG3

RF2RF3

VSS

RA

10R

A9

AVD

DAV

SSR

B8

RB

9R

B10

RB1

1

V DD

RF1

2R

F13

VSS

VDD

RD

15R

D14

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/RC

V/C

N25

/RB

7

RF5

RF4

RE5RE6RE7RC1RC2RC3RC4RG6

VDDRA0RE8RE9

RB3RB2

RG7RG8

PGEC1/AN1/RP1/CN3/RB1PGED1/AN0/RP0/CN2/RB0

RG15VDD

RG9MCLR

RB

12R

B13

RB

14R

B15

RG

1R

F1

RD

7R

D6

RA5

RA3RA2

VSSVS

S

VSS

ENVR

EG

RA4R

A1

RC14

RD10RD11

PGEC3/AN5/RP18/VBUSON/C1INA/CN7/RB5PGED3/AN4/RP28/USBOEN/C1INB/CN6/RB4

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 6 2007-2014 Microchip Technology Inc.

FIGURE 2-6: PIN DIAGRAMS (CONTINUED)

2345678910111213141516

4847

22

44

24 25 26 27 28 29 30 31 32

PIC24FJXXXGB106

1

4645

23

4342414039

RD

6R

D5

RD

4R

D3

RD

2R

D1

RE

4R

E3

RE

2R

E1

RF0

VCA

P/VD

DC

OR

E

RC13RD0

RD9RD8

RC15RC12VDDD+/RG2

VUSBVBUSRF3

D-/RG3

AVD

D

RB

8R

B9

RB1

0R

B11

V DD

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/RC

V/C

N25

/RB

7

RF5

RF4

RE5RE6RE7RG6

VDDPGEC3/AN5/RP18/VBUSON/C1INA/CN7/RB5PGED3/AN4/RP28/USBOEN/C1INB/CN6/RB4

RB3RB2

RG7RG8

PGEC1/AN1/RP1/VREF-/CN3/RB1PGED1/AN0/RP0/PMA6/VREF+/

RG9MCLR

RB1

2R

B13

RB1

4R

B15

RE

0R

F1

RD

7

VSS

VSS

VSS

ENVR

EG

63 62 61 5960 58 57 56 5455 53 52 51 4950

3837

34

3635

33

17 19 20 2118

AVSS

64

RC14

CN2/RB0

RD10RD11

64-Pin TQFP

2007-2014 Microchip Technology Inc. DS30009907C-page 7

PIC24FJXXXGA1/GB1 FAMILIES

FIGURE 2-7: PIN DIAGRAMS (CONTINUED)

80 79 78

20

23456789101112

1314

1516

6059

26

56

403928 29 30 31 32 33 34 35 36 37 38

PIC24FJXXXGB108

171819

1

7677

5857

27

5554535251

RD

5R

D4

RD

13R

D12

RD

3R

D2

RD

1

RE

2R

E1

RE

0R

G0

RE

4R

E3

RF0

VCA

P/VD

DC

OR

E

RC13RD0

RD9RD8RA15RA14

RC15RC12VDDD+/RG2

VUSBVBUSRF8

D-/RG3

RF2RF3

RA

10R

A9

AVD

D

RB

8R

B9

RB

10R

B11

VDD

RD

14R

D15

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/RC

V/C

N25

/RB

7

RF5

RF4

RE5RE6RE7RC1RC3RG6

VDDCN66/RE8CN67/RE9

PGEC3/AN5/RP18/VBUSON/PGED3/AN4/RP28/USBOEN/

RB3RB2

RG7RG8

PGEC1/AN1/RP1/CN3/RB1PGED1/AN0/RP0/CN2/RB0

RG9MCLR

RB

12R

B13

RB

14R

B15

RG

1R

F1

RD

7R

D6

VSS

VSS

VSS

ENVR

EG

75 74 73 7172 70 69 68 6667 65 64 63 6162

5049

46

4847

4544434241

21 23 24 2522

AVSS

C1INA/CN7/RB5C1INB/CN6/RB4

RC14

RD10RD11

80-Pin TQFP

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 8 2007-2014 Microchip Technology Inc.

FIGURE 2-8: PIN DIAGRAMS (CONTINUED)

9294 93 91 90 89 88 87 86 85 84 83 82 81 80 79 78

20

2345678910111213141516

65646362616059

26

564544434241403928 29 30 31 32 33 34 35 36 37 38

PIC24FJXXXGB110

171819

2122

95

1

7677

72717069686766

757473

5857

2423

25

9698 979927 46 47 48 49 50

5554535251

100

RD

5R

D4

RD

13R

D12

RD

3R

D2

RD

1

RA7

RA6

RE2

RG

13R

G12

RG

14R

E1R

E0

RG

0

RE4

RE3

RF0 VC

AP/

VDD

CO

RE

RC13RD0

RD9RD8RA15RA14

RC15RC12VDD

D+/RG2

VUSBVBUSRF8

D-/RG3

RF2RF3

VSS

RA

10R

A9

AVD

DAV

SSR

B8

RB

9R

B10

RB

11

V DD

RF1

2R

F13

VSS

VDD

RD

15R

D14

PGEC

2/A

N6/

RP6

/CN

24/R

B6

PGED

2/A

N7/

RP7

/RC

V/C

N25

/RB

7

RF5

RF4

RE5RE6RE7RC1RC2RC3RC4RG6

VDDRA0RE8RE9

RB3RB2

RG7RG8

PGEC1/AN1/RP1/CN3/RB1PGED1/AN0/RP0/CN2/RB0

RG15VDD

RG9MCLR

RB

12R

B13

RB

14R

B15

RG

1R

F1

RD

7R

D6

RA5

RA3RA2

VSS

VSS

VSS

ENVR

EGRA4

RA

1

RC14

RD10RD11

PGEC3/AN5/RP18/VBUSON/C1INA/CN7/RB5PGED3/AN4/RP28/USBOEN/C1INB/CN6/RB4

100-Pin TQFP

2007-2014 Microchip Technology Inc. DS30009907C-page 9

PIC24FJXXXGA1/GB1 FAMILIES

2.4 Memory MapThe program memory map extends from 000000h toFFFFFEh. Code storage is located at the base of thememory map and supports up to 87K instruction words(about 256 Kbytes). Table 2-2 shows the programmemory size, and number of erase and program blockspresent in each device variant. Each erase block, orpage, contains 512 instructions, and each programblock, or row, contains 64 instructions.

Locations, 800000h through 8007FEh, are reserved forexecutive code memory. This region stores the Pro-gramming Executive and the Debugging Executive.The Programming Executive is used for deviceprogramming and the Debugging Executive is used forin-circuit debugging. This region of memory can not beused to store user code.

The last three implemented program memory locationsare reserved for the Flash Configuration Words. Thereserved addresses are shown in Table 2-2.

Locations, FF0000h and FF0002h, are reserved for theDevice ID registers. These bits can be used by theprogrammer to identify what device type is beingprogrammed. They are described in Section 6.1“Device ID”. The Device ID registers read outnormally, even after code protection is applied.

Figure 2-9 shows the memory map for thePIC24FJXXXGA1/GB1 family variants.

TABLE 2-2: CODE MEMORY SIZE AND FLASH CONFIGURATION WORD LOCATIONS FOR PIC24FJXXXGA1/GB1 DEVICES

DeviceUser MemoryAddress Limit

(Instruction Words)

Write Blocks

Erase Blocks

Configuration Word Addresses

1 2 3

PIC24FJ64GA1XX00ABFEh (22K) 344 43 00ABFEh 00ABFCh 00ABFAh

PIC24FJ64GB1XXPIC24FJ128GA1XX

0157FEh (44K) 688 86 0157FEh 0157FCh 0157FAhPIC24FJ128GB1XXPIC24FJ192GA1XX

020BFEh (67K) 1048 131 020BFEh 020BFCh 020BFAPIC24FJ192GB1XXPIC24FJ256GA1XX

02ABFEh (87K) 1368 171 02ABFEh 02ABFCh 02ABFAPIC24FJ256GB1XX

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 10 2007-2014 Microchip Technology Inc.

FIGURE 2-9: PROGRAM MEMORY MAP

Use

r Mem

ory

Spac

e

000000h

Flash Configuration Words

Code Memory(1)

0XXX00h(1)0XXXFEh(1)

Con

figur

atio

n M

emor

ySp

ace

800000h

Device IDFEFFFEhFF0000h

FFFFFEh

Reserved

Reserved

8007FAh

800800h

Executive Code Memory

7FFFFEh

FF0002hFF0004hReserved

(2 x 16-bit)

Note 1: The size and address boundaries for user Flash code memory are device dependent. See Table 2-2 for details.

User Flash

(1024 x 24-bit)

8007F0hDiagnostic and Calibration Words

(8 x 24-bit)

0XXXFAh(1)0XXXF7h(1)

2007-2014 Microchip Technology Inc. DS30009907C-page 11

PIC24FJXXXGA1/GB1 FAMILIES

3.0 DEVICE PROGRAMMING – ICSPICSP mode is a special programming protocol thatallows you to read and write to the memory of thePIC24FJXXXGA1/GB1 devices. The ICSP mode is themost direct method used to program the device; note,however, that Enhanced ICSP is faster. ICSP modealso has the ability to read the contents of executivememory to determine if the Programming Executive ispresent. This capability is accomplished by applyingcontrol codes and instructions, serially to the device,using pins, PGCx and PGDx.

In ICSP mode, the system clock is taken from thePGCx pin, regardless of the device’s Oscillator Config-uration bits. All instructions are shifted serially into aninternal buffer, then loaded into the Instruction Register(IR) and executed. No program fetching occurs frominternal memory. Instructions are fed in 24 bits at atime. PGDx is used to shift data in, and PGCx is usedas both the serial shift clock and the CPU executionclock.

3.1 Overview of the Programming Process

Figure 3-1 shows the high-level overview of theprogramming process. After entering ICSP mode, thefirst action is to Chip Erase the device. Next, the codememory is programmed, followed by the deviceConfiguration registers. Code memory (including theConfiguration registers) is then verified to ensure thatprogramming was successful. Then, program thecode-protect Configuration bits, if required.

FIGURE 3-1: HIGH-LEVEL ICSP™ PROGRAMMING FLOW

3.2 ICSP OperationUpon entry into ICSP mode, the CPU is Idle. Executionof the CPU is governed by an internal state machine. A4-bit control code is clocked in using PGCx and PGDx,and this control code is used to command the CPU (seeTable 3-1).

The SIX control code is used to send instructions to theCPU for execution and the REGOUT control code isused to read data out of the device via the VISI register.

TABLE 3-1: CPU CONTROL CODES IN ICSP™ MODE

Note: During ICSP operation, the operatingfrequency of PGCx must not exceed10 MHz.

4-Bit Control Code Mnemonic Description

0000b SIX Shift in 24-bit instruction and execute.

0001b REGOUT Shift out the VISI (0784h) register.

0010b-1111b N/A Reserved.

Start

Perform ChipErase

Program Memory

Verify Program

Done

Enter ICSP™

Program Configuration Bits

Verify Configuration Bits

Exit ICSP

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 12 2007-2014 Microchip Technology Inc.

3.2.1 SIX SERIAL INSTRUCTION EXECUTION

The SIX control code allows execution of PIC24F familyassembly instructions. When the SIX code is received,the CPU is suspended for 24 clock cycles, as the instruc-tion is then clocked into the internal buffer. Once theinstruction is shifted in, the state machine allows it to beexecuted over the next four PGC clock cycles. While thereceived instruction is executed, the state machinesimultaneously shifts in the next 4-bit command (seeFigure 3-2).

Coming out of Reset, the first 4-bit control code isalways forced to SIX and a forced NOP instruction isexecuted by the CPU. Five additional PGCx clocks areneeded on start-up, resulting in a 9-bit SIX commandinstead of the normal 4-bit SIX command.After the forced SIX is clocked in, ICSP operationresumes as normal. That is, the next 24 clock cyclesload the first instruction word to the CPU.

FIGURE 3-2: SIX SERIAL EXECUTION

3.2.1.1 Differences Between Execution of SIX and Normal Instructions

There are some differences between executing instruc-tions normally and using the SIX ICSP command. As aresult, the code examples in this specification may notmatch those for performing the same functions duringnormal device operation.

The important differences are:

• Two-word instructions require two SIX operations to clock in all the necessary data.

Examples of two-word instructions are GOTO andCALL.

• Two-cycle instructions require two SIX operations.The first SIX operation shifts in the instruction andbegins to execute it. A second SIX operation, whichshould shift in a NOP to avoid losing data, providesthe CPU clocks required to finish executing theinstruction.

Examples of two-cycle instructions are Table Readand Table Write instructions.

• The CPU does not automatically stall to account for pipeline changes.

A CPU stall occurs when an instruction modifies aregister that is used for Indirect Addressing by thefollowing instruction.

During normal operation, the CPU will automaticallyforce a NOP while the new data is read. When usingICSP, there is no automatic stall, so any indirect ref-erences to a recently modified register should bepreceded by a NOP.For example, the instructions, MOV #0x0,W0 andMOV [W0],W1, must have a NOP inserted betweenthem.

If a two-cycle instruction modifies a register that isused indirectly, it will require two following NOPs: oneto execute the second half of the instruction and asecond to stall the CPU to correct the pipeline.

Instructions, such as TBLWTL [W0++],[W1],should be followed by two NOPs.

• The device Program Counter (PC) continues to automatically increment during ICSP instruction execution, even though the Flash memory is not being used.

As a result, the PC may be incremented to point toinvalid memory locations. Invalid memory spacesinclude unimplemented Flash addresses and thevector space (locations 0x0 to 0x1FF).

If the PC points to these locations, the device willreset, possibly interrupting the ICSP operation. Toprevent this, instructions should be periodicallyexecuted to reset the PC to a safe space. The opti-mal method to accomplish this is to perform aGOTO 0x200.

Note: To account for this forced NOP, all examplecode in this specification begins with aNOP to ensure that no data is lost.

P4

2 3 1 2 3 23 24 1 2 3 4P1

PGCxP4A

PGDx

24-Bit Instruction FetchExecute PC – 1,

1 6

0 0 0 0

Fetch SIX

4 5 6 7 8 18 19 20 21 2217

LSB X X X X X X X X X X X X X X MSB

PGDx = Input

P2

P3P1B

P1A

7 8 9

0 0 0 00 0 0

Only forProgram

Memory Entry

Control Code

4 5

Execute 24-BitInstruction, FetchNext Control Code

0 0

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3.2.2 REGOUT SERIAL INSTRUCTION EXECUTION

The REGOUT control code allows for data to be extractedfrom the device in ICSP mode. It is used to clock the con-tents of the VISI register, out of the device, over thePGDx pin. After the REGOUT control code is received, theCPU is held Idle for 8 cycles. After these 8 cycles, anadditional 16 cycles are required to clock the data out(see Figure 3-3).

The REGOUT code is unique because the PGDx pin isan input when the control code is transmitted to thedevice. However, after the control code is processed,the PGDx pin becomes an output as the VISI register isshifted out.

FIGURE 3-3: REGOUT SERIAL EXECUTION

Note 1: After the contents of VISI are shifted out,the PIC24FJXXXGA1/GB1 devices main-tain PGDx as an output until the firstrising edge of the next clock is received.

2: Data changes on the falling edge andlatches on the rising edge of PGCx. Forall data transmissions, the LeastSignificant bit (LSb) is transmitted first.

1 2 3 4 1 2 7 8PGCx

P4

PGDx

PGDx = Input

Execute Previous Instruction, CPU Held in Idle Shift Out VISI Register

P5

PGDx = Output

1 2 3 1 2 3 4

P4A

11 13 15 161412

No Execution Takes Place,Fetch Next Control Code

0 0 0 0 0

PGDx = Input

MSb1 2 3 41

4 5 6

LSb 141312... 11100

Fetch REGOUT Control Code

0

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3.3 Entering ICSP ModeAs shown in Figure 3-4, entering ICSP Program/Verifymode requires three steps:

1. MCLR is briefly driven high, then low.2. A 32-bit key sequence is clocked into PGDx.3. MCLR is then driven high within a specified

period of time and held.

The programming voltage applied to MCLR is VIH, whichis essentially VDD in the case of PIC24FJXXXGA1/GB1devices. There is no minimum time requirement for hold-ing at VIH. After VIH is removed, an interval of at least P18must elapse before presenting the key sequence onPGDx.

The key sequence is a specific 32-bit pattern:‘0100 1101 0100 0011 0100 1000 0101 0001’(more easily remembered as 4D434851h in hexa-decimal). The device will enter Program/Verify mode onlyif the sequence is valid. The Most Significant bit (MSb) ofthe most significant nibble must be shifted in first.

Once the key sequence is complete, VIH must beapplied to MCLR and held at that level for as long asProgram/Verify mode is to be maintained. An interval ofat least time, P19 and P7, must elapse before present-ing data on PGDx. Signals appearing on PGCx beforeP7 has elapsed will not be interpreted as valid.

On successful entry, the program memory can beaccessed and programmed in serial fashion. While inICSP mode, all unused I/Os are placed in thehigh-impedance state.

FIGURE 3-4: ENTERING ICSP™ MODE

MCLR

PGDx

PGCx

VDD

P6P14

b31 b30 b29 b28 b27 b2 b1 b0b3...

Program/Verify Entry Code = 4D434851h

P1AP1B

P18

P19

0 1 0 0 0 0

P7VIH VIH

101

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3.4 Flash Memory Programming in ICSP Mode

3.4.1 PROGRAMMING OPERATIONSFlash memory write and erase operations are controlledby the NVMCON register. Programming is performed bysetting NVMCON to select the type of erase operation(Table 3-2) or write operation (Table 3-3) and initiatingthe programming by setting the WR control bit(NVMCON).

In ICSP mode, all programming operations areself-timed. There is an internal delay between the usersetting the WR control bit and the automatic clearingof the WR control bit when the programming operationis complete. Please refer to Section 7.0 “AC/DCCharacteristics and Timing Requirements” forinformation about the delays associated with variousprogramming operations.

TABLE 3-2: NVMCON ERASE OPERATIONS

TABLE 3-3: NVMCON WRITE OPERATIONS

3.4.2 STARTING AND STOPPING A PROGRAMMING CYCLE

The WR bit (NVMCON) is used to start an erase orwrite cycle. Setting the WR bit initiates the programmingcycle.

All erase and write cycles are self-timed. The WR bitshould be polled to determine if the erase or write cyclehas been completed. Starting a programming cycle isperformed as follows:

3.5 Erasing Program MemoryThe procedure for erasing program memory (all of codememory, data memory, executive memory andcode-protect bits) consists of setting NVMCON to404Fh and executing the programming cycle.

A Chip Erase can erase all of user memory or all of boththe user and configuration memory. A Table Writeinstruction should be executed prior to performing theChip Erase to select which sections are erased.

When this Table Write instruction is executed:

• If the TBLPAG register points to user space (is less than 0x80), the Chip Erase will erase only user memory.

• If TBLPAG points to configuration memory space (is greater than or equal to 0x80), the Chip Erase will erase both user and configuration memory.

If configuration memory space is erased, theinternal oscillator Calibration Word, located at0x807FE, will be erased. This location should bestored prior to performing a whole Chip Erase andrestored afterward to prevent internal oscillatorsfrom becoming uncalibrated.

Figure 3-5 shows the ICSP programming process forperforming a Chip Erase. This process includes theICSP command code, which must be transmitted (foreach instruction), Least Significant bit first, using thePGCx and PGDx pins (see Figure 3-2).

FIGURE 3-5: CHIP ERASE FLOW

NVMCONValue Erase Operation

404Fh Erases all code memory, executive memory and Configuration registers (does not erase Unit ID or Device ID registers).

4042h Erases a page of code memory or executive memory.

NVMCONValue Write Operation

4003h Writes a Configuration Word register.4001h Programs 1 row (64 instruction words) of

code memory or executive memory.

BSET NVMCON, #WR

Note: Program memory must be erased beforewriting any data to program memory.

Start

Done

Set the WR bit to Initiate Erase

Write 404Fh to NVMCON SFR

Delay P11 + P10 Time

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TABLE 3-4: SERIAL INSTRUCTION EXECUTION FOR CHIP ERASECommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Set the NVMCON register to erase all program memory.00000000

2404FA883B0A

MOV #0x404F, W10MOV W10, NVMCON

Step 3: Set TBLPAG and perform dummy Table Write to select what portions of memory are erased.000000000000000000000000

200000880190200000BB0800000000000000

MOV #, W0MOV W0, TBLPAGMOV #0x0000, W0TBLWTL W0,[W0]NOPNOP

Step 4: Initiate the erase cycle.000000000000

A8E761000000000000

BSET NVMCON, #WR NOPNOP

Step 5: Repeat this step to poll the WR bit (bit 15 of NVMCON) until it is cleared by the hardware.0000000000000000000000010000

040200000000803B02883C22000000

000000

GOTO 0x200 NOPMOV NVMCON, W2MOV W2, VISINOPClock out contents of the VISI register.NOP

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3.6 Writing Code MemoryThe procedure for writing code memory is the same asthe procedure for writing the Configuration registers,except that 64 instruction words are programmed at atime. To facilitate this operation, Working registers,W0:W5, are used as temporary holding registers for thedata to be programmed.

Table 3-5 shows the ICSP programming details, includ-ing the serial pattern with the ICSP command code,which must be transmitted, Least Significant bit first,using the PGCx and PGDx pins (see Figure 3-2).

In Step 1, the Reset vector is exited. In Step 2, theNVMCON register is initialized for programming a fullrow of code memory. In Step 3, the 24-bit starting des-tination address for programming is loaded into theTBLPAG register and W7 register. (The upper byte ofthe starting destination address is stored in TBLPAGand the lower 16 bits of the destination address arestored in W7.)

To minimize the programming time, a packed instructionformat is used (Figure 3-6).

In Step 4, four packed instruction words are stored inWorking registers, W0:W5, using the MOV instructionand the Read Pointer, W6, is initialized. The contents ofW0:W5 (holding the packed instruction word data) areshown in Figure 3-6.

In Step 5, eight TBLWT instructions are used to copy thedata from W0:W5 to the write latches of code memory.Since code memory is programmed, 64 instructionwords at a time, Steps 4 and 5 are repeated 16 times toload all the write latches (Step 6).

After the write latches are loaded, programming isinitiated by writing to the NVMCON register in Steps 7and 8. In Step 9, the internal PC is reset to 200h. Thisis a precautionary measure to prevent the PC fromincrementing into unimplemented memory when largedevices are being programmed. Lastly, in Step 10,Steps 3-9 are repeated until all of code memory isprogrammed.

FIGURE 3-6: PACKED INSTRUCTION WORDS IN W0:W5

15 8 7 0W0 LSW0W1 MSB1 MSB0W2 LSW1W3 LSW2W4 MSB3 MSB2W5 LSW3

TABLE 3-5: SERIAL INSTRUCTION EXECUTION FOR WRITING CODE MEMORYCommand(Binary)

Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Set the NVMCON register to program 64 instruction words.00000000

24001A883B0A

MOV #0x4001, W10MOV W10, NVMCON

Step 3: Initialize the Write Pointer (W7) for the TBLWT instruction.000000000000

200xx08801902xxxx7

MOV #, W0MOV W0, TBLPAGMOV #, W7

Step 4: Load W0:W5 with the next 4 instruction words to program.000000000000000000000000

2xxxx02xxxx12xxxx22xxxx32xxxx42xxxx5

MOV #, W0MOV #, W1MOV #, W2MOV #, W3MOV #, W4MOV #, W5

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Step 5: Set the Read Pointer (W6) and load the (next set of) write latches.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

EB0300000000BB0BB6000000000000BBDBB6000000000000BBEBB6000000000000BB1BB6000000000000BB0BB6000000000000BBDBB6000000000000BBEBB6000000000000BB1BB6000000000000

CLR W6NOPTBLWTL [W6++], [W7] NOPNOPTBLWTH.B [W6++], [W7++] NOPNOPTBLWTH.B [W6++], [++W7] NOPNOPTBLWTL [W6++], [W7++] NOP NOPTBLWTL [W6++], [W7] NOPNOPTBLWTH.B [W6++], [W7++] NOP NOPTBLWTH.B [W6++], [++W7] NOPNOPTBLWTL [W6++], [W7++] NOPNOP

Step 6: Repeat Steps 4 and 5, sixteen times, to load the write latches for 64 instructions. Step 7: Initiate the write cycle.

000000000000

A8E761000000000000

BSET NVMCON, #WR NOPNOP

Step 8: Repeat this step to poll the WR bit (bit 15 of NVMCON) until it is cleared by the hardware.0000000000000000000000010000

040200000000803B02883C22000000

000000

GOTO 0x200 NOPMOV NVMCON, W2MOV W2, VISINOPClock out contents of the VISI register.NOP

Step 9: Reset the device internal PC.00000000

040200000000

GOTO 0x200 NOP

Step 10: Repeat Steps 3-9 until all code memory is programmed.

TABLE 3-5: SERIAL INSTRUCTION EXECUTION FOR WRITING CODE MEMORY (CONTINUED)Command(Binary)

Data(Hex) Description

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FIGURE 3-7: PROGRAM CODE MEMORY FLOW

Start Write Sequence

Alllocations

done?

No

Done

Start

Yes

Load 2 Bytesto Write

Buffer at

Allbytes

written?No

Yes

and Poll for WR bitto be Cleared

N = 1LoopCount = 0

ConfigureDevice for

Writes

N = 1LoopCount =

LoopCount + 1

N = N + 1

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DS30009907C-page 20 2007-2014 Microchip Technology Inc.

3.7 Writing Configuration WordsDevice configuration for PIC24FJXXXGA1/GB1 devicesis stored in Flash Configuration Words at the end of theuser space program memory, and in multiple registerConfiguration Words located in the test space. Theseregisters reflect values read at any Reset from programmemory locations. The values for the ConfigurationWords for the default device configurations are listed inTable 3-6.

The values can be changed only by programming thecontent of the corresponding Flash Configuration Wordand resetting the device. The Reset forces an automaticreload of the Flash stored configuration values bysequencing through the dedicated Flash ConfigurationWords and transferring the data into the Configurationregisters.

For the PIC24FJXXXGA1/GB1 families, certain Config-uration bits have default states that must always bemaintained to ensure device functionality, regardless ofthe settings of other Configuration bits. These bits andtheir values are listed in Table 3-7.

To change the values of the Flash Configuration Wordonce it has been programmed, the device must be ChipErased, as described in Section 3.5 “Erasing ProgramMemory”, and reprogrammed to the desired value. It isnot possible to program a ‘0’ to ‘1’, but they may beprogrammed from a ‘1’ to ‘0’ to enable code protection.

TABLE 3-6: DEFAULT CONFIGURATION REGISTER VALUES

TABLE 3-7: RESERVED CONFIGURATION BIT LOCATIONS

Table 3-8 shows the ICSP programming details for pro-gramming the Configuration Word locations, includingthe serial pattern with the ICSP command code whichmust be transmitted, Least Significant bit first, using thePGCx and PGDx pins (see Figure 3-2).

In Step 1, the Reset vector is exited. In Step 2, theNVMCON register is initialized for programming ofcode memory. In Step 3, the 24-bit starting destinationaddress for programming is loaded into the TBLPAGregister and W7 register.

The TBLPAG register must be loaded with thefollowing:

• 64-Kbyte devices: 00h• 128, 192 and 256-Kbyte devices: 01h

To verify the data by reading the Configuration Wordsafter performing the write in order, the code protectionbits initially should be programmed to a ‘1’ to ensurethat the verification can be performed properly. Afterverification is finished, the code protection bits can beprogrammed to a ‘0’ by using a word write to theappropriate Configuration Word.

Address Name Default Value

Last Word CW1 7FFFhLast Word – 2 CW2 F7FFhLast Word – 4 CW3 FFFFh

Bit Location Value

CW1 0CW1 1CW2 0CW2(1) 1Note 1: This bit is implemented as I2C2SEL on

PIC24FJXXXGA110 devices and should be programmed as required.

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TABLE 3-8: SERIAL INSTRUCTION EXECUTION FOR WRITING CONFIGURATION REGISTERSCommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Initialize the Write Pointer (W7) for the TBLWT instruction.0000 2xxxx7 MOV , W7

Step 3: Set the NVMCON register to program CW2.00000000

24003A883B0A

MOV #0x4003, W10MOV W10, NVMCON

Step 4: Initialize the TBLPAG register.00000000

200xx0880190

MOV , W0MOV W0, TBLPAG

Step 5: Load the Configuration register data to W6.0000 2xxxx6 MOV #, W6

Step 6: Write the Configuration register data to the write latch and increment the Write Pointer.0000000000000000

000000BB1B86000000000000

NOPTBLWTL W6, [W7++]NOPNOP

Step 7: Initiate the write cycle.000000000000

A8E761000000000000

BSET NVMCON, #WRNOPNOP

Step 8: Repeat this step to poll the WR bit (bit 15 of NVMCON) until it is cleared by the hardware.0000000000000000000000010000

040200000000803B02883C22000000

000000

GOTO 0x200NOPMOV NVMCON, W2MOV W2, VISINOPClock out contents of the VISI register.NOP

Step 9: Reset the device internal PC.00000000

040200000000

GOTO 0x200NOP

Step 10: Repeat Steps 5-9 to write CW1.

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3.8 Reading Code MemoryReading from code memory is performed by executinga series of TBLRD instructions and clocking out the datausing the REGOUT command.Table 3-9 shows the ICSP programming details forreading code memory. In Step 1, the Reset vector isexited. In Step 2, the 24-bit starting source address forreading is loaded into the TBLPAG register and W6register. The upper byte of the starting source addressis stored in TBLPAG and the lower 16 bits of the sourceaddress are stored in W6.

To minimize the reading time, the packed instructionword format that was utilized for writing is also used forreading (see Figure 3-6). In Step 3, the Write Pointer,W7, is initialized. In Step 4, two instruction words areread from code memory and clocked out of the device,through the VISI register, using the REGOUT command.Step 4 is repeated until the desired amount of codememory is read.

TABLE 3-9: SERIAL INSTRUCTION EXECUTION FOR READING CODE MEMORYCommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Initialize the TBLPAG register and the Read Pointer (W6) for the TBLRD instruction.000000000000

200xx08801902xxxx6

MOV #, W0MOV W0, TBLPAGMOV #, W6

Step 3: Initialize the Write Pointer (W7) to point to the VISI register.00000000

207847000000

MOV #VISI, W7 NOP

Step 4: Read and clock out the contents of the next two locations of code memory, through the VISI register, using the REGOUT command.

000000000000000100000000000000000000000000000001000000000000000000010000

BA0B96000000000000

000000BADBB6000000000000BAD3D6000000000000

000000BA0BB6000000000000

000000

TBLRDL [W6], [W7] NOPNOPClock out contents of VISI registerNOPTBLRDH.B [W6++], [W7++]NOPNOPTBLRDH.B [++W6], [W7--]NOPNOPClock out contents of VISI registerNOPTBLRDL [W6++], [W7]NOPNOPClock out contents of VISI registerNOP

Step 5: Repeat Step 4 until all desired code memory is read. Step 6: Reset the device internal PC.

00000000

040200000000

GOTO 0x200 NOP

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3.9 Reading Configuration WordsThe procedure for reading configuration memory issimilar to the procedure for reading code memory,except that 16-bit data words are read instead of 24-bitwords. Configuration Words are read, one register at atime.

Table 3-10 shows the ICSP programming details forreading the Configuration Words. Note that theTBLPAG register must be loaded with 00h for 64-Kbytedevices, 01h for 128-Kbyte devices, and 02h for192-Kbyte and 256-Kbyte devices (the upper byteaddress of configuration memory), and the ReadPointer, W6, is initialized to the lower 16 bits of theConfiguration Word location.

TABLE 3-10: SERIAL INSTRUCTION EXECUTION FOR READING ALL CONFIGURATION MEMORYCommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Initialize the TBLPAG register, the Read Pointer (W6) and the Write Pointer (W7) for the TBLRD instruction.00000000000000000000

200xx08801902xxxx6207846000000

MOV , W0MOV W0, TBLPAGMOV , W6MOV #VISI, W7NOP

Step 3: Read the Configuration register and write it to the VISI register (located at 784h), and clock out the VISI register using the REGOUT command.

00000000000000010000

BA0BB6000000000000

000000

TBLRDL [W6++], [W7] NOP NOPClock out contents of VISI registerNOP

Step 4: Repeat Step 3 twice to read Configuration Word 2 and Configuration Word 1. Step 5: Reset the device internal PC.

00000000

040200000000

GOTO 0x200 NOP

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3.10 Verify Code Memory and Configuration Word

The verify step involves reading back the code memoryspace and comparing it against the copy held in theprogrammer’s buffer. The Configuration registers areverified with the rest of the code.

The verify process is shown in the flowchart inFigure 3-8. Memory reads occur a single byte at a time,so two bytes must be read to compare against the wordin the programmer’s buffer. Refer to Section 3.8“Reading Code Memory” for implementation detailsof reading code memory.

FIGURE 3-8: VERIFY CODE MEMORY FLOW

3.11 Reading the Application ID WordThe Application ID Word is stored at address,8007F0h, in executive code memory. To read thismemory location, you must use the SIX control code tomove this program memory location to the VISI regis-ter. Then, the REGOUT control code must be used toclock the contents of the VISI register out of the device.The corresponding control and instruction codes thatmust be serially transmitted to the device to performthis operation are shown in Table 3-11.

After the programmer has clocked out the ApplicationID Word, it must be inspected. If the Application ID hasthe value, CBh, the Programming Executive is residentin memory and the device can be programmed usingthe mechanism described in Section 4.0 “DeviceProgramming – Enhanced ICSP”. However, if theApplication ID has any other value, the ProgrammingExecutive is not resident in memory; it must be loadedto memory before the device can be programmed. Theprocedure for loading the Programming Executive tomemory is described in Section 5.4 “Programmingthe Programming Executive to Memory”.

3.12 Exiting ICSP ModeExiting Program/Verify mode is done by removing VIHfrom MCLR, as shown in Figure 3-9. The only require-ment for exit is that an interval, P16, should elapsebetween the last clock and program signals on PGCxand PGDx before removing VIH.

FIGURE 3-9: EXITING ICSP™ MODE

Note: Because the Configuration registersinclude the device code protection bit,code memory should be verified immedi-ately after writing if code protection isenabled. This is because the device willnot be readable or verifiable if a deviceReset occurs after the code-protect bit inCW1 has been cleared.

Read Low Byte

Read High Byte

DoesWord = Expect

Data?

Failure,ReportError

Allcode memory

verified?

No

Yes

No

Set TBLPTR = 0

Start

Yes

Done

with Post-Increment

with Post-Increment

MCLR

P16

PGDx

PGD = Input

PGCx

VDD

VIH

VIH

P17

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TABLE 3-11: SERIAL INSTRUCTION EXECUTION FOR READING THE APPLICATION ID WORDCommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Initialize the TBLPAG register and the Read Pointer (W0) for the TBLRD instruction.00000000000000000000000000000000

200800880190207F00207841000000BA0890000000000000

MOV #0x80, W0 MOV W0, TBLPAGMOV #0x7F0, W0 MOV #VISI, W1 NOP TBLRDL [W0], [W1] NOPNOP

Step 3: Output the VISI register using the REGOUT command.00010000

000000

Clock out contents of the VISI registerNOP

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4.0 DEVICE PROGRAMMING – ENHANCED ICSP

This section discusses programming the devicethrough Enhanced ICSP and the Programming Execu-tive. The Programming Executive resides in executivememory (separate from code memory) and is executedwhen Enhanced ICSP Programming mode is entered.The Programming Executive provides the mechanismfor the programmer (host device) to program and verifythe PIC24FJXXXGA1/GB1 devices using a simplecommand set and communication protocol. There areseveral basic functions provided by the ProgrammingExecutive:

• Read Memory• Erase Memory• Program Memory• Blank Check• Read Executive Firmware Revision

The Programming Executive performs the low-leveltasks required for erasing, programming and verifyinga device. This allows the programmer to program thedevice by issuing the appropriate commands and data.Table 4-1 summarizes the commands. A detaileddescription for each command is provided inSection 5.2 “Programming Executive Commands”.

TABLE 4-1: COMMAND SET SUMMARY

The Programming Executive uses the device’s dataRAM for variable storage and program execution. Afterthe Programming Executive has run, no assumptionsshould be made about the contents of data RAM.

4.1 Overview of the Programming Process

Figure 4-1 shows the high-level overview of theprogramming process. After entering Enhanced ICSPmode, the Programming Executive is verified. Next, thedevice is erased. Then, the code memory isprogrammed, followed by the configuration locations.Code memory (including the Configuration registers) isthen verified to ensure that programming was successful.

After the Programming Executive has been verifiedin memory (or loaded if not present), thePIC24FJXXXGA1/GB1 families can be programmedusing the command set shown in Table 4-1.

FIGURE 4-1: HIGH-LEVEL ENHANCED ICSP™ PROGRAMMING FLOW

4.2 Confirming the Presence of the Programming Executive

Before programming can begin, the programmer mustconfirm that the Programming Executive is stored inexecutive memory. The procedure for this task isshown in Figure 4-2.

First, In-Circuit Serial Programming (ICSP) mode isentered. Then, the unique Application ID Word stored inexecutive memory is read. If the Programming Executiveis resident, the Application ID Word is CBh, which meansprogramming can resume as normal. However, if theApplication ID Word is not CBh, the ProgrammingExecutive must be programmed to executive codememory using the method described in Section 5.4“Programming the Programming Executive toMemory”. Section 3.0 “Device Programming – ICSP” describesthe ICSP programming method. Section 3.11 “Readingthe Application ID Word” describes the procedure forreading the Application ID Word in ICSP mode.

Command Description

SCHECK Sanity CheckREADC Read Device ID RegistersREADP Read Code Memory PROGP Program One Row of Code Memory

and VerifyPROGW Program One Word of Code Memory

and VerifyQBLANK Query if the Code Memory is BlankQVER Query the Software Version

Start

Done

Perform ChipErase

Program Memory

Verify Program

Enter Enhanced ICSP™

Program Configuration Bits

Verify Configuration Bits

Exit Enhanced ICSP

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FIGURE 4-2: CONFIRMING PRESENCE OF PROGRAMMING EXECUTIVE

4.3 Entering Enhanced ICSP ModeAs shown in Figure 4-3, entering Enhanced ICSPProgram/Verify mode requires three steps:

1. The MCLR pin is briefly driven high, then low.2. A 32-bit key sequence is clocked into PGDx.3. MCLR is then driven high within a specified

period of time and held.

The programming voltage applied to MCLR is VIH,which is essentially VDD in the case ofPIC24FJXXXGA1/GB1 devices. There is no minimumtime requirement for holding at VIH. After VIH isremoved, an interval of at least P18 must elapse beforepresenting the key sequence on PGDx.

The key sequence is a specific 32-bit pattern:‘0100 1101 0100 0011 0100 1000 0101 0000’(more easily remembered as 4D434850h in hexa-decimal format). The device will enter Program/Verifymode only if the key sequence is valid. The MostSignificant bit (MSb) of the most significant nibble mustbe shifted in first.

Once the key sequence is complete, VIH must beapplied to MCLR and held at that level for as long asProgram/Verify mode is to be maintained. An interval ofat least time, P19 and P7, must elapse before present-ing data on PGDx. Signals appearing on PGDx beforeP7 has elapsed will not be interpreted as valid.

On successful entry, the program memory can beaccessed and programmed in serial fashion. While inthe Program/Verify mode, all unused I/Os are placed inthe high-impedance state.

FIGURE 4-3: ENTERING ENHANCED ICSP™ MODE

Is

Start

Enter ICSP™ Mode

Application IDCBh?

Resident in Memory

Yes

No

Prog. Executive is

Application IDRead the

be ProgrammedProg. Executive must

from Address807F0h

Finish

MCLR

PGDx

PGCx

VDD

P6P14

b31 b30 b29 b28 b27 b2 b1 b0b3...

Program/Verify Entry Code = 4D434850h

P1AP1B

P18

P19

0 1 0 0 1 0 0 0 0

P7VIH VIH

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4.4 Blank CheckThe term, “Blank Check”, implies verifying that thedevice has been successfully erased and has noprogrammed memory locations. A blank or erasedmemory location is always read as ‘1’. The Device ID registers (FF0002h:FF0000h) can beignored by the Blank Check since this region storesdevice information that cannot be erased. The deviceConfiguration registers are also ignored by the BlankCheck. Additionally, all unimplemented memory spaceshould be ignored by the Blank Check.

The QBLANK command is used for the Blank Check. Itdetermines if the code memory is erased by testingthese memory regions. A ‘BLANK’ or ‘NOT BLANK’response is returned. If it is determined that the deviceis not blank, it must be erased before attempting toprogram the chip.

4.5 Code Memory Programming

4.5.1 PROGRAMMING METHODOLOGYCode memory is programmed with the PROGPcommand. PROGP programs one row of code memory,starting from the memory address specified in thecommand. The number of PROGP commands requiredto program a device depends on the number of writeblocks that must be programmed in the device.

A flowchart for programming the code memory of thePIC24FJXXXGA1/GB1 families is shown in Figure 4-4.In this example, all 87K instruction words of a256-Kbyte device are programmed. First, the numberof commands to send (called, ‘RemainingCmds’, in theflowchart) is set to 1368 and the destination address(called, ‘BaseAddress’) is set to ‘0’. Next, one writeblock in the device is programmed with a PROGPcommand. Each PROGP command contains data forone row of code memory of the device. After the firstcommand is processed successfully, ‘RemainingCmds’is decremented by 1 and compared with 0. Since thereare more PROGP commands to send, ‘BaseAddress’ isincremented by 80h to point to the next row of memory.

On the second PROGP command, the second row isprogrammed. This process is repeated until the entiredevice is programmed. No special handling must beperformed when a panel boundary is crossed.

FIGURE 4-4: FLOWCHART FOR PROGRAMMING CODE MEMORY

4.5.2 PROGRAMMING VERIFICATIONAfter code memory is programmed, the contents ofmemory can be verified to ensure that programmingwas successful. Verification requires code memory tobe read back and compared against the copy held inthe programmer’s buffer.

The READP command can be used to read back all ofthe programmed code memory.

Alternatively, you can have the programmer performthe verification after the entire device is programmedusing a checksum computation.

IsPROGP response

PASS?

AreRemainingCmds

0?

BaseAddress = 00hRemainingCmds = 1368

RemainingCmds =RemainingCmds – 1

BaseAddress =BaseAddress + 80h

No

No

Yes

Yes

Start

FailureReport Error

Send PROGPCommand to Program

BaseAddress

Finish

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4.6 Configuration Bits Programming

4.6.1 OVERVIEWThe PIC24FJXXXGA1/GB1 families have Configurationbits stored in the last three locations of implementedprogram memory (see Table 2-2 for locations). Thesebits can be set or cleared to select various device config-urations. There are three types of Configuration bits:system operation bits, code-protect bits and unit ID bits.The system operation bits determine the power-onsettings for system level components, such as theoscillator and Watchdog Timer. The code-protect bitsprevent program memory from being read and written.

The descriptions for the Configuration bits in the FlashConfiguration Words are shown in Table 4-2.

Note: Although not implemented with a specificfunction, some Configuration bit positionshave default states that must always bemaintained to ensure device functionality,regardless of the settings of other Config-uration bits. Refer to Table 3-7 for a list ofthese bit positions and their default states.

TABLE 4-2: PIC24FJXXXGA1/GB1 FAMILIES CONFIGURATION BITS DESCRIPTIONBit Field Register Description

DEBUG CW1 Background Debug Enable bit1 = Device will reset in User mode0 = Device will reset in Debug mode

DISUVREG(1) CW2 Internal USB 3.3V Regulator Disable bit1 = Regulator is disabled0 = Regulator is enabled

FCKSM CW2 Clock Switching Mode bits1x = Clock switching is disabled, Fail-Safe Clock Monitor is disabled01 = Clock switching is enabled, Fail-Safe Clock Monitor is disabled00 = Clock switching is enabled, Fail-Safe Clock Monitor is enabled

FNOSC CW2 Initial Oscillator Source Selection bits111 = Internal Fast RC (FRCDIV) Oscillator with Postscaler110 = Reserved101 = Low-Power RC (LPRC) Oscillator100 = Secondary Oscillator (SOSC)011 = Primary Oscillator with PLL (XTPLL, HSPLL, ECPLL)010 = Primary Oscillator (XT, HS, EC) 001 = Internal Fast RC Oscillator with Postscaler and PLL (FRCPLL)000 = Fast RC (FRC) Oscillator

FWDTEN CW1 Watchdog Timer Enable bit1 = Watchdog Timer is always enabled (LPRC oscillator cannot be disabled;

clearing the SWDTEN bit in the RCON register will have no effect)0 = Watchdog Timer is enabled/disabled by user software (LPRC can be

disabled by clearing the SWDTEN bit in the RCON register)FWPSA CW1 Watchdog Timer Postscaler bit

1 = 1:1280 = 1:32

GCP CW1 General Segment Code-Protect bit1 = User program memory is not code-protected0 = User program memory is code-protected

GWRP CW1 General Segment Write-Protect bit1 = User program memory is not write-protected0 = User program memory is write-protected

Note 1: Available on PIC24FJXXXGB1XX devices only.2: Available on PIC24FJXXXGA110 devices only. On other devices, always maintain this bit as ‘1’.

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I2C2SEL(2) CW2 I2C2 Pin Select bit (PIC24FJXXXGA1XX devices only)1 = Uses SCL2/SDA2 pins for I2C™ Module 20 = Uses ASCL2/ASDA2 pins for I2C Module 2

ICS CW1 ICD Emulator Pin Placement Select bits11 = Emulator functions are shared with PGEC1/PGED110 = Emulator functions are shared with PGEC2/PGED201 = Emulator functions are shared with PGEC3/PGED300 = Reserved; do not use

IESO CW2 Internal External Switchover bit1 = Two-Speed Start-up is enabled0 = Two-Speed Start-up is disabled

IOL1WAY CW2 IOLOCK Bit One-Way Set Enable bit0 = The OSCCON bit can be set and cleared as needed

(provided an unlocking sequence is executed)1 = The OSCCON bit can only be set once (provided an

unlocking sequence is executed); once IOLOCK is set, this prevents anypossible future RP register changes

JTAGEN CW1 JTAG Enable bit1 = JTAG is enabled 0 = JTAG is disabled

OSCIOFNC CW2 OSC2 Pin Function bit (except in XT and HS modes)1 = OSC2 is a clock output0 = OSC2 is a general purpose digital I/O pin

PLLDIV(1) CW2 USB 96 MHz PLL Prescaler Select bits111 = Oscillator input divided by 12 (48 MHz input)110 = Oscillator input divided by 10 (40 MHz input)101 = Oscillator input divided by 6 (24 MHz input)100 = Oscillator input divided by 5 (20 MHz input)011 = Oscillator input divided by 4 (16 MHz input)010 = Oscillator input divided by 3 (12 MHz input)001 = Oscillator input divided by 2 (8 MHz input)000 = Oscillator input is used directly (4 MHz input)

POSCMD CW2 Primary Oscillator Mode Select bits11 = Primary Oscillator mode is disabled10 = HS Crystal Oscillator mode01 = XT Crystal Oscillator mode00 = EC (External Clock) mode

WDTPS CW1 Watchdog Timer Prescaler bits1111 = 1:32,7681110 = 1:16,384 . . .0001 = 1:20000 = 1:1

TABLE 4-2: PIC24FJXXXGA1/GB1 FAMILIES CONFIGURATION BITS DESCRIPTION (CONTINUED)Bit Field Register Description

Note 1: Available on PIC24FJXXXGB1XX devices only.2: Available on PIC24FJXXXGA110 devices only. On other devices, always maintain this bit as ‘1’.

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WINDIS CW1 Windowed WDT bit1 = Watchdog Timer is in Non-Window mode0 = Watchdog Timer is in Window mode; FWDTEN must be ‘1’

WPCFG CW3 Configuration Word Code Page Protection Select bit1 = Last page (at the top of program memory) and Flash Configuration

Words are not protected0 = Last page and Flash Configuration Words are code-protected

WPDIS CW3 Segment Write Protection Disable bit1 = Segmented code protection is disabled0 = Segmented code protection is enabled; protected segment defined by

the WPEND, WPCFG and WPFPx Configuration bitsWPEND CW3 Segment Write Protection End Page Select bit

1 = Protected code segment lower boundary is at the bottom of programmemory (000000h); upper boundary is the code page specified byWPFP

0 = Protected code segment upper boundary is at the last page of programmemory; lower boundary is the code page specified by WPFP

WPFP CW3 Protected Code Segment Boundary Page bitsDesignates the 512 instruction words page boundary of the protected code segment.If WPEND = 1:Specifies the lower page boundary of the code-protected segment; the last page being the last implemented page in the device.If WPEND = 0:Specifies the upper page boundary of the code-protected segment; Page 0 being the lower boundary.

TABLE 4-2: PIC24FJXXXGA1/GB1 FAMILIES CONFIGURATION BITS DESCRIPTION (CONTINUED)Bit Field Register Description

Note 1: Available on PIC24FJXXXGB1XX devices only.2: Available on PIC24FJXXXGA110 devices only. On other devices, always maintain this bit as ‘1’.

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4.6.2 PROGRAMMING METHODOLOGYConfiguration bits may be programmed a single byte ata time using the PROGP command. This commandspecifies the configuration data and Configurationregister address. When Configuration bits areprogrammed, any unimplemented or reserved bitsmust be programmed with a ‘1’.Four PROGW commands are required to program theConfiguration bits. A flowchart for Configuration bitprogramming is shown in Figure 4-5.

4.6.3 PROGRAMMING VERIFICATIONAfter the Configuration bits are programmed, thecontents of memory should be verified to ensure thatthe programming was successful. Verification requiresthe Configuration bits to be read back and comparedagainst the copy held in the programmer’s buffer. TheREADP command reads back the programmedConfiguration bits and verifies that the programmingwas successful.

FIGURE 4-5: CONFIGURATION BIT PROGRAMMING FLOW

Note: If the General Segment Code-Protect bit(GCP) is programmed to ‘0’, code memoryis code-protected and can not be read.Code memory must be verified beforeenabling read protection. See Section 4.6.4“Code-Protect Configuration Bits” formore information about code-protectConfiguration bits.

Send PROGPCommand

ConfigAddress = 0XXXF8h(1)

IsPROGP response

PASS?

No

Yes

No

FailureReport Error

Start

Finish

Yes

IsConfigAddress0XXXFEh?(1)

ConfigAddress =ConfigAddress + 2

Note 1: Refer to Table 2-2 for Flash Configuration Word addresses.

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4.6.4 CODE-PROTECT CONFIGURATION BITS

PIC24FJXXXGA1/GB1 family devices provide twocomplimentary methods to protect application codefrom overwrites and erasures. These also help to pro-tect the device from inadvertent configuration changesduring run time. Additional information is available inthe product data sheet.

4.6.4.1 GENERAL SEGMENT PROTECTION

For all devices in the PIC24FJXXXGA1/GB1 families,the on-chip program memory space is treated as asingle block, known as the General Segment (GS).Code protection for this block is controlled by one Con-figuration bit, GCP. This bit inhibits external reads andwrites to the program memory space. It has no directeffect in normal execution mode.

Write protection is controlled by the GWRP bit in theConfiguration Word. When GWRP is programmed to‘0’, internal write and erase operations to programmemory are blocked.

4.6.4.2 CODE SEGMENT PROTECTIONIn addition to global General Segment protection, aseparate subrange of the program memory space canbe individually protected against writes and erases.This area can be used for many purposes where aseparate block of write and erase-protected code isneeded, such as bootloader applications. Unlikecommon boot block implementations, the specially pro-tected segment in PIC24FJXXXGA1/GB1 devices canbe located by the user anywhere in the program space,and configured in a wide range of sizes.

Code segment protection provides an added level ofprotection to a designated area of program memory bydisabling the NVM safety interlock whenever a write orerase address falls within a specified range. It does notoverride General Segment protection controlled by theGCP or GWRP bit. For example, if GCP and GWRPare enabled, enabling segmented code protection forthe bottom half of program memory does not undoGeneral Segment protection for the top half.

4.7 Exiting Enhanced ICSP ModeExiting Program/Verify mode is done by removing VIHfrom MCLR, as shown in Figure 4-6. The only require-ment for exit is that an interval, P16, should elapsebetween the last clock, and program signals on PGCxand PGDx, before removing VIH.

FIGURE 4-6: EXITING ENHANCED ICSP™ MODE

Note: Bulk Erasing in ICSP mode is the only wayto reprogram code-protect bits from an ONstate (‘0’) to an OFF state (‘1’).

MCLR

P16

PGDx

PGDx = Input

PGCx

VDD

VIH

VIH

P17

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5.0 THE PROGRAMMING EXECUTIVE

5.1 Programming Executive Communication

The programmer and Programming Executive have amaster-slave relationship, where the programmer isthe master programming device and the ProgrammingExecutive is the slave.

All communication is initiated by the programmer in theform of a command. Only one command at a time canbe sent to the Programming Executive. In turn, theProgramming Executive only sends one response tothe programmer after receiving and processing acommand. The Programming Executive command setis described in Section 5.2 “Programming ExecutiveCommands”. The response set is described inSection 5.3 “Programming Executive Responses”.

5.1.1 COMMUNICATION INTERFACE AND PROTOCOL

The Enhanced ICSP interface is a 2-wire SPI,implemented using the PGCx and PGDx pins. ThePGCx pin is used as a clock input pin and the clocksource must be provided by the programmer. ThePGDx pin is used for sending command data to, andreceiving response data from, the ProgrammingExecutive.

Data transmits to the device must change on the risingedge and hold on the falling edge. Data receives fromthe device must change on the falling edge and hold onthe rising edge.

All data transmissions are sent to the Most Significantbit (MSb) first, using 16-bit mode (see Figure 5-1).

FIGURE 5-1: PROGRAMMING EXECUTIVE SERIAL TIMING FOR DATA RECEIVED FROM DEVICE

FIGURE 5-2: PROGRAMMING EXECUTIVE SERIAL TIMING FOR DATA TRANSMITTED TO DEVICE

Since a 2-wire SPI is used, and data transmissions arehalf-duplex, a simple protocol is used to control thedirection of PGDx. When the programmer completes acommand transmission, it releases the PGDx line andallows the Programming Executive to drive this linehigh. The Programming Executive keeps the PGDx linehigh to indicate that it is processing the command.

After the Programming Executive has processed thecommand, it brings PGDx low for 15 s to indicate to theprogrammer that the response is available to be clockedout. The programmer can begin to clock out theresponse, 23 s after PGDx is brought low, and it mustprovide the necessary amount of clock pulses to receivethe entire response from the Programming Executive.

After the entire response is clocked out, the program-mer should terminate the clock on PGCx until it is timeto send another command to the ProgrammingExecutive. This protocol is shown in Figure 5-3.

5.1.2 SPI RATEIn Enhanced ICSP mode, the PIC24FJXXXGA1/GB1devices operate from the Internal Fast RC oscillator(FRCDIV), which has a nominal frequency of 8 MHz.This oscillator frequency yields an effective systemclock frequency of 4 MHz. To ensure that the program-mer does not clock too fast, it is recommended that a4 MHz clock be provided by the programmer.

5.1.3 TIME-OUTSThe Programming Executive uses no Watchdog Timeror time-out for transmitting responses to the program-mer. If the programmer does not follow the flow controlmechanism using PGCx, as described in Section 5.1.1“Communication Interface and Protocol”, it ispossible that the Programming Executive will behaveunexpectedly while trying to send a response to theprogrammer. Since the Programming Executive has notime-out, it is imperative that the programmer correctlyfollow the described communication protocol.

As a safety measure, the programmer should use thecommand time-outs identified in Table 5-1. If the com-mand time-out expires, the programmer should resetthe Programming Executive and start programming thedevice again.

PGCx

PGDx

1 2 3 11 13 15 161412

LSb14 13 12 11

4 5 6

MSb 123... 45

P2

P3

P1

P1BP1A

PGCx

PGDx

1 2 3 11 13 15 161412

LSb14 13 12 11

4 5 6

MSb 123... 45

P2

P3

P1

P1BP1A

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FIGURE 5-3: PROGRAMMING EXECUTIVE – PROGRAMMER COMMUNICATION PROTOCOL

5.2 Programming Executive Commands

The Programming Executive command set is shown inTable 5-1. This table contains the opcode, mnemonic,length, time-out and description for each command.Functional details on each command are provided inSection 5.2.4 “Command Descriptions”.

5.2.1 COMMAND FORMATAll Programming Executive commands have a generalformat consisting of a 16-bit header and any requireddata for the command (see Figure 5-4). The 16-bitheader consists of a 4-bit opcode field, which is used toidentify the command, followed by a 12-bit commandlength field.

FIGURE 5-4: COMMAND FORMAT

The command opcode must match one of those in thecommand set. Any command that is received whichdoes not match the list in Table 5-1 will return a “NACK”response (see Section 5.3.1.1 “Opcode Field”). The command length is represented in 16-bit wordssince the SPI operates in 16-bit mode. The Program-ming Executive uses the command length field todetermine the number of words to read from the SPIport. If the value of this field is incorrect, the commandwill not be properly received by the ProgrammingExecutive.

5.2.2 PACKED DATA FORMATWhen 24-bit instruction words are transferred acrossthe 16-bit SPI interface, they are packed to conservespace using the format shown in Figure 5-5. Thisformat minimizes traffic over the SPI and provides theProgramming Executive with data that is properlyaligned for performing Table Write operations.

FIGURE 5-5: PACKED INSTRUCTION WORD FORMAT

5.2.3 PROGRAMMING EXECUTIVE ERROR HANDLING

The Programming Executive will “NACK” allunsupported commands. Additionally, due to thememory constraints of the Programming Executive, nochecking is performed on the data contained in theprogrammer command. It is the responsibility of theprogrammer to command the Programming Executivewith valid command arguments or the programmingoperation may fail. Additional information on errorhandling is provided in Section 5.3.1.3 “QE_CodeField”.

1 2 15 16 1 2 15 16

PGCx

PGDx

PGCx = Input PGCx = Input (Idle)

Host TransmitsLast Command Word

PGDx = Input PGDx = Output

P8

1 2 15 16

MSB X X X LSB MSB X X X LSB MSB X X X LSB1 0P20

PGCx = InputPGDx = Output

P9

Programming ExecutiveProcesses Command Host Clocks Out Response

P21

15 12 11 0Opcode Length

Command Data First Word (if required)••

Command Data Last Word (if required)

Note: When the number of instruction wordstransferred is odd, MSB2 is zero andLSW2 can not be transmitted.

15 8 7 0LSW1

MSB2 MSB1LSW2

LSWx: Least Significant 16 bits of instruction wordMSBx: Most Significant Bytes of instruction word

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TABLE 5-1: PROGRAMMING EXECUTIVE COMMAND SET

5.2.4 COMMAND DESCRIPTIONSAll commands supported by the Programming Executiveare described in Section 5.2.5 “SCHECK Command”through Section 5.2.12 “QVER Command”.

5.2.5 SCHECK COMMAND

The SCHECK command instructs the ProgrammingExecutive to do nothing but generate a response. Thiscommand is used as a “Sanity Check” to verify that theProgramming Executive is operational.

Expected Response (2 words):1000h0002h

Opcode Mnemonic Length(16-bit words) Time-out Description

0h SCHECK 1 1 ms Sanity check.1h READC 3 1 ms Read an 8-bit word from the specified Device ID register.2h READP 4 1 ms/row Read N 24-bit instruction words of code memory starting from

the specified address.3h RESERVED N/A N/A This command is reserved; it will return a NACK.4h PROGC 4 5 ms Write an 8-bit word to the specified Device ID registers.5h PROGP 99 5 ms Program one row of code memory at the specified address,

then verify.(1)

Dh PROGW 4 5 ms Program one instruction word of code memory at the specified address, then verify.

7h RESERVED N/A N/A This command is reserved; it will return a NACK.8h RESERVED N/A N/A This command is reserved; it will return a NACK.9h RESERVED N/A N/A This command is reserved; it will return a NACK.Ah QBLANK 3 30 ms/Kbyte Query if the code memory is blank.Bh QVER 1 1 ms Query the Programming Executive software version.

Note 1: One row of code memory consists of (64) 24-bit words. Refer to Table 2-2 for device-specific information.

15 12 11 0Opcode Length

Field Description

Opcode 0hLength 1h

Note: This instruction is not required forprogramming but is provided fordevelopment purposes only.

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5.2.6 READC COMMAND

The READC command instructs the Programming Exec-utive to read N or Device ID registers, starting from the24-bit address specified by Addr_MSB and Addr_LS.This command can only be used to read 8-bit or 16-bitdata.

When this command is used to read Device IDregisters, the upper byte in every data word returned bythe Programming Executive is 00h and the lower bytecontains the Device ID register value.

Expected Response (4 + 3 * (N – 1)/2 words for N odd):1100h2 + NDevice ID Register 1... Device ID Register N

5.2.7 READP COMMAND

The READP command instructs the Programming Exec-utive to read N 24-bit words of code memory, includingConfiguration Words, starting from the 24-bit addressspecified by Addr_MSB and Addr_LS. This commandcan only be used to read 24-bit data. All data returned inresponse to this command uses the packed data formatdescribed in Section 5.2.2 “Packed Data Format”.Expected Response (2 + 3 * N/2 words for N even):

1200h2 + 3 * N/2Least Significant Program Memory Word 1... Least Significant Data Word N

Expected Response (4 + 3 * (N – 1)/2 words for N odd):1200h

4 + 3 * (N – 1)/2

Least Significant Program Memory Word 1

...

MSB of Program Memory Word N (zero-padded)

15 12 11 8 7 0Opcode Length

N Addr_MSBAddr_LS

Field Description

Opcode 1hLength 3hN Number of 8-bit Device ID registers to

read (max. of 256)Addr_MSB MSB of 24-bit source addressAddr_LS Least Significant 16 bits of 24-bit

source address

Note: Reading unimplemented memory willcause the Programming Executive toreset. Please ensure that only memorylocations present on a particular deviceare accessed.

15 12 11 8 7 0Opcode Length

NReserved Addr_MSB

Addr_LS

Field Description

Opcode 2hLength 4hN Number of 24-bit instructions to read

(max. of 32768)Reserved 0hAddr_MSB MSB of 24-bit source addressAddr_LS Least Significant 16 bits of 24-bit

source address

Note: Reading unimplemented memory willcause the Programming Executive toreset. Please ensure that only memorylocations present on a particular deviceare accessed.

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5.2.8 PROGC COMMAND

The PROGC command instructs the Programming Exec-utive to program a single Device ID register located atthe specified memory address.

After the specified data word has been programmed tocode memory, the Programming Executive verifies theprogrammed data against the data in the command.

Expected Response (2 words):1400h0002h

5.2.9 PROGP COMMAND

The PROGP command instructs the Programming Exec-utive to program one row of code memory, includingConfiguration Words (64 instruction words), to thespecified memory address. Programming begins withthe row address specified in the command. Thedestination address should be a multiple of 80h.

The data to program to memory, located in commandwords, D_1 through D_96, must be arranged using thepacked instruction word format shown in Figure 5-5.

After all data has been programmed to code memory,the Programming Executive verifies the programmeddata against the data in the command.

Expected Response (2 words):1500h0002h

15 12 11 8 7 0Opcode Length

Reserved Addr_MSBAddr_LS

Data

Field Description

Opcode 4hLength 4hReserved 0hAddr_MSB MSB of 24-bit destination addressAddr_LS Least Significant 16 bits of 24-bit

destination addressData 8-bit data word

15 12 11 8 7 0Opcode Length

Reserved Addr_MSBAddr_LS

D_1D_2...

D_96

Field Description

Opcode 5hLength 63hReserved 0hAddr_MSB MSB of 24-bit destination addressAddr_LS Least Significant 16 bits of 24-bit

destination addressD_1 16-bit Data Word 1D_2 16-bit Data Word 2... 16-bit Data Word 3 through 95D_96 16-bit Data Word 96

Note: Refer to Table 2-2 for code memory sizeinformation.

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5.2.10 PROGW COMMAND

The PROGW command instructs the Programming Exec-utive to program one word of code memory (3 bytes) tothe specific memory address.

After the word has been programmed to code memory,the Programming Executive verifies the programmeddata against the data in the command.

Expected Response (2 words):1D00h0002h

5.2.11 QBLANK COMMAND

The QBLANK command queries the ProgrammingExecutive to determine if the contents of code memoryand code-protect Configuration bits (GCP and GWRP)are blank (contain all ‘1’s). The size of code memory tocheck must be specified in the command.

The Blank Check for code memory begins at 0h andadvances toward larger addresses for the specifiednumber of instruction words.

QBLANK returns a QE_Code of F0h if the specifiedcode memory and code-protect bits are blank;otherwise, QBLANK returns a QE_Code of 0Fh.Expected Response (2 words for blank device):

1AF0h

0002h

Expected Response (2 words for non-blank device):1A0Fh

0002h

15 12 11 8 7 2 1 0Opcode Length

Data_MSB Addr_MSBAddr_LSData_LS

Field Description

Opcode DhLength 4hAddr_MSB MSB of 24-bit destination addressAddr_LS Least Significant 16 bits of 24-bit

destination addressData_MSB MSB of 24-bit dataData_LS Least Significant 16 bits of 24-bit data

15 12 11 0Opcode Length

PSize_MSWPSize_LSW

Field Description

Opcode AhLength 3hPSize Length of program memory to check

in 24-bit words plus one (max. of 49152)

Note: QBLANK does not check the systemoperation Configuration bits, since thesebits are not set to ‘1’ when a Chip Erase isperformed.

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5.2.12 QVER COMMAND

The QVER command queries the version of theProgramming Executive software stored in testmemory. The “version.revision” information is returnedin the response’s QE_Code using a single byte with thefollowing format: main version in upper nibble andrevision in the lower nibble (i.e., 23h means Version 2.3of Programming Executive software).

Expected Response (2 words):1BMNh (where “MN” stands for Version M.N)0002h

5.3 Programming Executive Responses

The Programming Executive sends a response to theprogrammer for each command that it receives. Theresponse indicates if the command was processedcorrectly. It includes any required response data orerror data.

The Programming Executive response set is shown inTable 5-2. This table contains the opcode, mnemonicand description for each response. The response formatis described in Section 5.3.1 “Response Format”.

TABLE 5-2: PROGRAMMING EXECUTIVE RESPONSE OPCODES

5.3.1 RESPONSE FORMATAll Programming Executive responses have a generalformat consisting of a two-word header and anyrequired data for the command.

5.3.1.1 Opcode FieldThe opcode is a 4-bit field in the first word of theresponse. The opcode indicates how the commandwas processed (see Table 5-2). If the command wasprocessed successfully, the response opcode is PASS.If there was an error in processing the command, theresponse opcode is FAIL and the QE_Code indicatesthe reason for the failure. If the command sent tothe Programming Executive is not identified, theProgramming Executive returns a NACK response.

5.3.1.2 Last_Cmd FieldThe Last_Cmd is a 4-bit field in the first word ofthe response and indicates the command that theProgramming Executive processed. Since the Pro-gramming Executive can only process one commandat a time, this field is technically not required. However,it can be used to verify that the Programming Executivecorrectly received the command that the programmertransmitted.

15 12 11 0Opcode Length

Field Description

Opcode BhLength 1h

Opcode Mnemonic Description

1h PASS Command successfully processed

2h FAIL Command unsuccessfully processed

3h NACK Command not known

Field Description

Opcode Response opcodeLast_Cmd Programmer command that

generated the responseQE_Code Query code or error code.Length Response length in 16-bit words

(includes 2 header words)D_1 First 16-bit data word (if applicable)D_N Last 16-bit data word (if applicable)

15 12 11 8 7 0

Opcode Last_Cmd QE_Code

Length

D_1 (if applicable)

...

D_N (if applicable)

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5.3.1.3 QE_Code FieldThe QE_Code is a byte in the first word of theresponse. This byte is used to return data for querycommands and error codes for all other commands.

When the Programming Executive processes one ofthe two query commands (QBLANK or QVER), thereturned opcode is always PASS and the QE_Codeholds the query response data. The format of theQE_Code for both queries is shown in Table 5-3.

TABLE 5-3: QE_Code FOR QUERIES

When the Programming Executive processes anycommand other than a query, the QE_Code representsan error code. Supported error codes are shown inTable 5-4. If a command is successfully processed, thereturned QE_Code is set to 0h, which indicates thatthere was no error in the command processing. If theverify of the programming for the PROGP or PROGCcommand fails, the QE_Code is set to 1h. For all otherProgramming Executive errors, the QE_Code is 2h.

TABLE 5-4: QE_Code FOR NON-QUERY COMMANDS

5.3.1.4 Response LengthThe response length indicates the length of theProgramming Executive’s response in 16-bit words.This field includes the 2 words of the response header.

With the exception of the response for the READPcommand, the length of each response is only 2 words.

The response to the READP command uses the packedinstruction word format described in Section 5.2.2“Packed Data Format”. When reading an odd numberof program memory words (N odd), the response to theREADP command is (3 * (N + 1)/2 + 2) words. Whenreading an even number of program memory words(N even), the response to the READP command is(3 * N/2 + 2) words.

Query QE_Code

QBLANK 0Fh = Code memory is NOT blankF0h = Code memory is blank

QVER 0xMN, where Programming Executive software version = M.N (i.e., 32h means Software Version 3.2)

QE_Code Description

0h No error1h Verify failed2h Other error

PIC24FJXXXGA1/GB1 FAMILIES

DS30009907C-page 42 2007-2014 Microchip Technology Inc.

5.4 Programming the Programming Executive to Memory

5.4.1 OVERVIEWIf it is determined that the Programming Executive isnot present in executive memory (as described inSection 4.2 “Confirming the Presence of the Pro-gramming Executive”), it must be programmed intoexecutive memory using ICSP, as described inSection 3.0 “Device Programming – ICSP”.

Storing the Programming Executive to executivememory is similar to normal programming of codememory. Namely, the executive memory must beerased and then the Programming Executive must beprogrammed, 64 words at a time. Erasing the last pageof executive memory will cause the FRC oscillatorcalibration settings, and device diagnostic data in theDiagnostic and Calibration Words, at addresses,8007F0h to 8007FEh, to be erased. In order to retainthis calibration, these memory locations should be readand stored prior to erasing executive memory. Theyshould then be reprogrammed in the last words of pro-gram memory. This control flow is summarized inTable 5-5.

TABLE 5-5: PROGRAMMING THE PROGRAMMING EXECUTIVECommand

(Binary)Data(Hex) Description

Step 1: Exit the Reset vector and erase executive memory.000000000000

000000040200000000

NOPGOTO 0x200NOP

Step 2: Initialize the pointers to read the Diagnostic and Calibration Words for storage in W6-W13.00000000000000000000

200800880190207F012000C2000000

MOV #0x80, W0MOV W0, TBLPAGMOV #0x07F0, W1MOV #0xC, W2NOP

Step 3: Repeat this step 8 times to read the Diagnostic and Calibration Words, storin