Lab. 1 GPIO Pin controlUsing information ENEL353 and ENCM369 text books combined with Blackfin DATA manual

D Flip flopD input is captured by the first latch of the D-Flip-flop on rising edge of a clock signal C,The output of the first latch is captured by a second D-flip-flop using an inverted clock signalThus the input to the D flip flop appears at its output on the falling edge of the clock after being captured on the rising edge of the clock* /25

N flip-flops form a registerPutting 32 of this flip-flops together form a register If this register is internal to the processor core -- system register -- R0, P0, SP, FP, CYCLESIf external to the core or on another device not a system register

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Memory mapped registerThe D input values come along the memory data busWhich register is used is controlled by the value on the memory data busThe address of the register and the data value placed into the register is controlled by normal memory instructions issues by the processor* /25

* /25Building a radio controlled car4 Threads at leastSWITCHES ON FRONT PANEL INPUT COMMANDS:PROGRAMMABLE FLAGSFIO_FLAG_D Register

YOUR PROGRAM RUNNING ON THE BLACKFINLED LIGHTS ON FRONT PANEL CONTROLSIGNALS TO RF TRANS:LED-CONTROLREGISTEREBIU INTERFACEProcessDataASM( ) subroutineA/D D/A Interrupt routineD/AEAR PHONESA/DVOICEint ReadSwitches( )void WriteLED(int )

* /25Registers used to control PF pinsFlag Data register (FIO_FLAG_D)Used to read the PF bits as an input -- (1 or 0)Need to read pins PF11 to PF8, ignore all other pins values

Instructions need to access FIO_FLAG_DSet address bus P0.L = lo(FIO_FLAG_D); P0,H = hi(..Read R0 = [P0] (X) (32, 16, or 8)?Write [P0] = R0 (32, 16, or 8)?Select one bit R3 = 0x0100; R2 = R3 & R0;Force one bit R2 = R3 | R0;DONT DESTROY VALUE R0 = R3 & R0* /25

Flip flopsWhen they power up in an unknown state could be 1 or 0, On power up -- processor designed to put flip-flop into known state reset valueWhether set to 1 or 0 depends on what flip-flop output is connected toSafety reasons sometimes reset to 0 or reset to 1* /25

Flip flops have set and clear capabilityMake SET = 1, and toggle clock and output becomes 1Make SET = 0, and toggle clock and output become 0

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FLIPFLOPSET

FLIPFLOPCLEAR* /25

Other GPIO Flip flopsFIO_MASKA_D and FIO_MASKB_DIf bit X = 1, tell processor to cause interrupt when FIO_FLAG_D bit X is active* /25

Interrupt mask registersalso have their own set / clear linesFIO_MASKA_C, FIO_MASKB_CFIO_MASKA_S, FIO_MASKB_S* /25

Other flip-flop group tell processor whether to interrupt on input changing or steady. This register has no meaning if interrupts are not active* /25

Another flipflop group tells processor1) interrupt on rising / fail edge if EDGE = 12) interrupt on high level or low level if EDGE = 0* /25

Same flipflop group tells processor1) if no interrupt then output of flipflop equals the Q output of flipflop2) If no interrupt then output of flipflop equals Q* output of flipflop* /25

Another flip-flop group controls whether the flip-flop outputs follow the flip-flop inputs or are high impedance off no useful value* /25

A key issue with GPIO is whether a pin is to act as an input device (bringing things in from the outside world into the Blackfin) or as an output device (sending things from the Blackfin to the outside world)* /25

* /25Why do you need to know how to do read (load) and write (store) on internal registers?Flag Direction register (FIO_DIR)Used to determine if the PF bit is to be used for input or output -- WARNING SMOKE POSSIBLE ISSUENeed to set pins PF11 to PF8 for input, leave all other pins unchanged

* /25Write the Blackfin assembly language instruction(s) to load the address of the internal programmable flag FIO_DIR register into pointer register P1 then SET the Blackfin PF lines to act as inputs

Making sure that the FIO_DIR is correct for LAB. 1 NOTE may need to change for later labaoratoriesDesign Error Changes all pins

#include #include P1.L = lo (FIO_DIR);P1.H = hi (FIO_DIR);

// Check the requirements need to have all input// Manual says setting a line for input means setting bit values to 0R0 = 0;W[P1] = R0; // This changes All pinsssync; // Force Blackfin to do the write (store) NOW not later

Notice that previous slide WARNS you about a design error in the codeWe cant do things this way as it changes all the bits in the 16 flip-flops and we only want to change 4 values in the flip-flopsThe same design error is introduced into Lab. 1 Task 3However, the same design error is found during the TDD tests provided to look at the test code to see what was being tested * /25

These tests DONOT find the design error* /25

These tests DO find the design errorand in fact explain to you why it is likely that your tests have failed. But you have to read it* /25

This test is another indication that you have not written the code correctly. There must be 12 read and writes not 6, not 3* /25

We have other tests to check that your code is correct Lab. 1 Task 4People come by and said I have the cable correct, but it keeps on telling me I dont meaning I did not look at the test to see what it was doing so Dr. Smith your Lab. Is wrong* /25

* /25Task Initialize the Programmable flag interface 16 I/O lines on the BlackfinWarning could burn out the Blackfin processor if done incorrectly

You need to set (store a known value to) a number of Blackfin internal registersMost important onesFIO_DIR Data DIRection 0 for input ****FIO_INEN INterface ENable 1 for enabledFIO_FLAG_D Programmable FLAG Data register

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Setting FIO_DIR to zero for ONLY pins 8, 9, 10 and 11. Other pins unchanged

P1.L = lo (FIO_DIR); // #include knows FIO_DIR valueP1.H = hi (FIO_DIR);// R0 = 0; // DESIGN ERROR changes all pins to 0// W[P1] = R0; // This changes All pins

// Correct approach use an AND mask operationR1 = W[P1]; // Read the current valueR2 = 0x0F00 (Z); // Prepare the 32-bit mask with bits // 8 to 11 set to 1, other bits 0R2 = ~R2; // Complement operation // bits 8 to 11 are 0, other bits 1R3 = R1 & R2; // R3 bits = 0 for bits 8 to 11; // R3 bits = FIO_DIR bits otherwiseW[P1] = R3; // Restore FIO DIR with bits 8 to 11 set to 0, ssync; // Force Blackfin to do the write (store) NOW not later

* /25Registers used to control PF pinsFlag Input Enable RegisterOnly activate the pins you want to use (saves power in telecommunications situation)Need to activate pins PF11 to PF8 for input, leave all other pins unchanged

* /25Write the Blackfin assembly language instruction(s) to load the address of the internal programmable flag FIO_INEN register into pointer register P1 then ENABLE the Blackfin PF lines as inputs

Making sure that the FIO_INEN is correct for enable of pins 8 to 11Design Error Changes all pins

#include #include P1.L = lo (FIO_?????);P1.H = hi (FIO_?????);

// Check the requirements need to have all input// Manual says setting a line for input means setting bit values to 0R0 = 0x0F00;W[P1] = R0; // This changes All pins 8 to 11 ON (enable), others OFFssync; // Force Blackfin to do the write (store) NOW not later

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Setting FIO_INEN to one for ONLY pins 8, 9, 10 and 11. Other pins unchanged

P1.L = lo (FIO_???); // #include knows FIO_INEN valueP1.H = hi (FIO_???);// R0 = 0x0F00; // DESIGN ERROR changes all pins// W[P1] = R0; // This changes All pins

// Correct approach use an AND mask operationR1 = W[P1]; // Read the current valueR2 = 0x0F00 (Z); // Prepare the 32-bit mask with bits // 8 to 11 set to 1, other bits 0R3 = R1 | R2; // R3 bits = 1 for bits 8 to 11; // R3 bits = FIO_DIR bits otherwiseW[P1] = R3; // Restore FIO INEN with bits 8 to 11 set to 1, ssync; // Force Blackfin to do the write (store) NOW not later

* /25Task Setting up the programmable flag interfaceFollow the instructions carefullyFIO_DIR direction register write 0s to bits 8 to 11FIO_INEN input enable register write 1s to bits 8, 9, 10, 11Other bits leave unchanged:

To provide a screen dump of the test result to show your code worksUse PRT-SCR button and then paste in .doc file.In Lab. 1. the task said -- Check the following bit patterns in the manual pages 14-1 to 14-22 to make sure that I have got the patterns around the correct way.

* /25Echoing the switches to the LEDCode in main( ) written in C++int main( ) {InitializeGPIOInterface( ); // Check Lab. 1 for exact name needed InitializeFlashLEDInterface( ); // Check Lab. 1 for exact name needed

#define SWITCHBITS 0x0F00 // Look in MIPs notes about // using a mask and the // AND bit-wise operation // to select desired bits while (1) { // Forever loop int GPIO_value = ReadBlackfinGPIOFlagsASM ( ); int desired_bits = GPIO_value & SWITCHBITS; int LED_light_values = desired_bits >> 8; // Bits in wrong position WriteFlashLEDLights(LED_light_values); // to display on LEDS }}

* /25Building a radio controlled car4 Threads at leastSWITCHES ON FRONT PANEL INPUT COMMANDS:PROGRAMMABLE FLAGSFIO_FLAG_D Register

YOUR PROGRAM RUNNING ON THE BLACKFINLED LIGHTS ON FRONT PANEL CONTROLSIGNALS TO RF TRANS:LED-CONTROLREGISTEREBIU INTERFACEProcessDataASM( ) subroutineA/D D/A Interrupt routineD/AEAR PHONESA/DVOICEint ReadSwitches( )void WriteLED(int )

Blackfin BF533 I/O*LEDs connected to FLASH portBACK FORWARD RIGHT LEFT ???CONTROL ON Might be connected to other things DONT CHANGE BEHAVIOUR

Blackfin BF533 I/O

Blackfin BF533 I/O*Blackfin Memory MapIf P0 is 0x20001000 then R0 = [P0]; reads a value from FLASH BANK 0

If R0 is 6 and P0 is 0x1000 then [P0] = R0; places a value into SDRAM

Blackfin BF533 I/O

Blackfin BF533 I/O*Set the Bank control registerKit documentation recommends 0x7BB07 cycles not 15

11 not 15

B = 1011

2 cycles

3 cycles

IGNORE

4cycles

Blackfin BF533 I/O

Blackfin BF533 I/O*Set General Control RegisterDocumentation says set to 0xF for this particular FLASH chipENABLE

ALL

Blackfin BF533 I/O

Blackfin BF533 I/O*WriteFlashLEDASM(long in_value)Read LED data register into processor data register (makes a copy)Keep top 2 bits (AND operation) of copyKeep bottom 6 bits of in-par 32-bit in_valueOR the two processor data registers Write modified copy back into LED data registerPROBLEM byte read and writes

Blackfin BF533 I/O

* /25Laboratory 1 TasksDownload the C++ Talk-through program. Board check -- Check that you can hear the audio outputDevelop and test the code for initializing the Flash Memory and writing to the LEDsUse the provided tests to check your codeRoutine for initializing the PF GPIO lines (programmable flags)Use the provided tests to check your codeDevelop the ReadProgrammableFlagsASM( ) to read the switchesUse the provided tests to check your codeDevelop the Morse code program in C++ and ASM