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Microprocessors &
Microcontrollers
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Microprocessor ?
A microprocessor is multi programmable clock driven
register basedsemiconductor device that isused to fetch , process and
execute a data withinfraction of seconds.
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Microprocessors
• CPU for Computers
• No RAM, ROM, I/O on CPU chip itself
• Example Intel!s x"#, Motorola$s #"%x%
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Microcontroller
• A smaller computer• Onchip RAM, ROM, I/O ports'''
• Example Motorola$s #"((, Intel$s "%)(,
*ilo+$s *" an PIC
Suresh.P.Nair , HOD - ECE , RCET 4
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Microprocessor vs.Microcontroller
Microprocessor• CPU is stanalone, RAM,
ROM, I/O, timer areseparate
• -esi+ner can ecie onthe amount of ROM, RAMan I/O ports'
•
Expansi.e
• ersatilit0
• 1eneralpurpose
Microcontroller• CPU, RAM, ROM, I/O an
timer are all on a sin+lechip
• 2ix amount of onchipROM, RAM, I/O ports
• 2or applications in 3hich
cost, po3er an space arecritical
• Not Expansi.e
• 4in+lepurpose5
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Microprocessor ?
A microprocessor is multi programmable clock driven
register basedsemiconductor device that isused to fetch , process and
execute a data withinfraction of seconds.
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56E "%") AN- I54 7U44E4
The 8085 is an 8-bit general purposemicroprocessor64K Byte of memory.It has 40 pins.
It can run at a maximum freuency of ! "#$.
%&&ress Bus.'(6 bit) *ata Bus. '8 bit)
+ontrol an& ,tatus ,ignals.oer supply an& freuency./xternally Initiate& ,ignals.,erial I1 ports.
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2la+ Re+ister
CYCYPP AC ACZZSSD0D0D1D1D2D2D3D3D4D4D5D5D6D6DD
The flags are affected by the arithmetic and logical
instruction
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Classi8cation of instructionset
According to word size orbyte size it is classied into
3 types. 1 byte instruction
! byte instruction and
3 byte instruction
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( 90te instruction
"t includes the #pcode and the#perand in the same byte.
$x. %#& A,'$x. (%) '
$x. A*A '
$x. +A
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Opcoe an operan
-he task to be performedis called #pcode
-he data to be operated iscalled #perand.
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: 90te instruction
-he rst byte species theoperation cod eand the next
byte species the operand$x. %&" A, 1
$x. /0" A, 3
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; 90te instruction
-he rst byte species theopcode and the next two
bytes species the 12 bitaddressdata.
$x. 4" 5, 6
$x. 7%) 6
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Timing Diagram is a graphical representation. Itrepresents the execution time taken by eachinstruction in a graphical format. The execution
time is represented in T-states.
Instruction Cycle: The time required to execute an instruction .
Machine Cycle: The time required to access the memory orinputoutput de!ices .
T-"tate:•The machine cycle and instruction cycle takesmultiple clock periods. •# portion of an operation carried out in one
system clock period is called as T-state. !"##e!$e% &' C.(")u# AP*EEE,+CET
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5imin+ ia+rams• The 8085 microprocessor has 7 basic machine
cycle. They are
1. Op-code Fetch cycle(4T or 6T).
. !emory read cycle ("T)
". !emory #rite cycle("T)
4. $%O read cycle("T)
5. $%O #rite cycle("T)6. $nterr&pt 'cno#lede cycle(6T or 1T)
7. *&s idle cycle
!"##e!$e% &' C.(")u# AP*EEE,+CET
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!"##e!$e% &' C.(")u# AP*EEE,+CET
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45A instructionex STA 526A
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It re;5 ;'memor0 rea>;5
='Memor0 3rite>;5
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Timing diagram for INC0H
• Fetcing te !pcode "#H fromte memor$ %&25H.
• 'ead te port address C0H from%&26H.
• 'ead te content of port C0H andsend it to te acc(m(lator.
• )et te content of port is 5*H.
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It re=5memor0 rea>;5
I/O rea>;5
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!+T
instr(ctionMacines
C$cles,&0T-&.instr(ction fetc,%T-
2.memor$ read ,/T-/.I! rite ,/T-
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Classi1cation ofInstr(ction Set
• -ata 5ransfer Instruction
• Arithmetic Instructions
• @o+ical Instructions
• 7ranchin+ Instructions
• Control Instructions
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IN5ER2ACIN1
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":)) PPI• 5he 255 chip is also calle as
3rogramma4le 3eriperal Interface'
• 5he Intel$s ":)) is esi+ne for use 3ithIntel$s "9it, (#9it an hi+her capa9ilit0microprocessors
• It is exi9le an economical'
CON5RO@ BOR-
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CON5RO@ BOR-RE1I45ER>CBR
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Modes of !peration of255
#it Set'eset,#S'- ModeSet'eset 4its in 3ort C
I! Mode Mode 0 ,Simple inp(to(tp(t- Mode & ,Handsae mode- Mode 2 ,#idirectional "ata
Transfer-
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7rite a program to initiali8e 255 in tecon1g(ration 4elo.,ass(me address of teC7 register as 2/H-.,&- 3ort A o(tp(t it andsae,2- 3ort # inp(t it andsae
,/- 3ort C) o(tp(t ,%-3ort C+ inp(t
Sol(tion
& 0 & 0 & & & 0 = AEH
M9I A:A*H ; LOAD CONTROL WORD
!+T 2/H ; SEND CONTROL WORD
Program:
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Find te control ord for te registerarrangementof te ports of Intel 255 for mode 0operation.3ort A !(tp(t: 3ort # !(tp(t: 3ort C+ !(tp(t: 3ort C) !(tp(t
Solution:
& 0 0 0 0 0 0 0 = 80H
The ontrol !or" regi#ter $or the a%o&e'ort# o$ (ntel 8)** i# 80H+
#asics of serial
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#asics of serialcomm(nication
&.Transmitter A parallelin, serialoutshift re+ister
2.'eceiver A serialin, paralleloutshift re+ister'
2
Parallel Tran#$er
TRANS,(TTER
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TRANS,(TTER
Reei&er
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IN5E@ ":)(U4AR5
+,$/' 2,3/O,O+
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+ ,$/' 2,3/O,O+
'2,3/O,O+ / 3$/
T/',!$TT/ (+'/T-Pro+ramma9le chip esi+ne fors0nchronous an as0nchronous serial atatransmission
:" pin -IP
Co.erts the parallel ata into a serial stream of 9its suita9le for serial
transmission' Recei.es a serial stream of 9its an con.ert
it into parallel ata 90tes to 9e rea 90 amicroprocessor'
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IN5E@ ":);/":)=
5IMER/COUN5ER
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INT*) 2;< =
3rogramma4le>e$4oard"ispla$
Interface
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"%)( 2amil0
• 5he "%)( is a su9set of the "%):
• 5he "%;( is a ROMless "%)( – A external ROM to it
– ou lose t3o ports, an lea.e onl0 : ports for I/Ooperations
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(nterru'tControl
CP-
./ RO,
)8 1RA,
OSC1u#
Control. (2O Port#
SerialPort
of 05&
T3D R3DP0 P P) P4
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"%)( Memor0 4tructure
E 5 t e r n a l
E3T (NT)8
S6R E 5 t e r n a l
P ,Data ,emor7
./ ./
EA =0
EA =
./
0/
051 i!r"!"/$r"##er Suresh PNair HOD ECE RCET 3