The Microprocessor System. A semester course review. Summarize important points for whole subject. Using the 8051 architecture as the practical and projects development.

1. Microprocessor System
Summarize
Apr 2009
Hisham Mat Hussin
Senior Lecturer (Electronics)
University Kuala Lumpur-BMI

2. Contents:Introduction
Block Diagram and Pin Description of the 8051
Registers
Some Simple Instructions
Structure of Assembly language and Running an
8051 program
Memory mapping in 8051
8051 Flag bits and the PSW register
Addressing Modes
16-bit, BCD and Signed Arithmetic in 8051
Stack in the 8051
LOOP and JUMP Instructions
CALL Instructions
I/O Port Programming

3. Numerical Bases Used in
Programming
• Hexadecimal
• Binary
• Decimal

4. Hexadecimal Basis
• Hexadecimal Digits:
0 1 2 3 4 5 6 7 8 9 A B C D E F
A=10
B=11
C=12
D=13
E=14
F=15

5. Decimal, Binary &
Hexadecimal Numbers
(43)10=
( 0010 1011 )2 =
( 2 B )16

6. Introduction
• CPU for Computers
• No RAM, ROM, I/O on CPU chip itself
• Example ： Intel’s x86, Motorola’s 680x0
CPU
General-
Purpose
Micro-
processor
RAM ROM I/O
Port
Timer
Serial
COM
Port
Data Bus
Address Bus
General-Purpose Microprocessor System
Many chips on mother’s board
General-purpose microprocessor

7. General-purpose microprocessor

8. • A smaller computer
• On-chip RAM, ROM, I/O ports...
• Example ： Motorola’s 6811, Intel’s 8051, Zilog’s Z8 and PIC 16X
RAM ROM
I/O
Port
Timer
Serial
COM
Port
Microcontroller
CPU
A single chip
Microcontroller :

9. Micro-
controller
Microcontroller Application :

12. Microprocessor
• CPU is stand-alone, RAM,
ROM, I/O, timer are
separate
• designer can decide on the
amount of ROM, RAM and
I/O ports.
• expansive
• versatility
• general-purpose
Microcontroller
• CPU, RAM, ROM, I/O and
timer are all on a single chip
• fix amount of on-chip ROM,
RAM, I/O ports
• for applications in which cost,
power and space are critical
• single-purpose
Microprocessor vs. Microcontroller

13. Inside the
Microprocessor
INTEL 4004
(1971)

14. • Embedded system means the processor is embedded into
that application.
• An embedded product uses a microprocessor or
microcontroller to do one task only.
• In an embedded system, there is only one application
software that is typically burned into ROM.
• Example ： printer, keyboard, video game player
Embedded System

15. The Intel 8051
microcontroller

16. The Intel 8051 microcontroller system circuitry
Intel
8051

17. Overview of the 8051 Family
One of the oldest (Intel MCS-51 in 1981) and probably the most
popular microcontroller. Many derivatives are marketed by a number
of manufacturers
Common features,
– 8-bit processor
– 4 I/O ports each 8bits wide
– max of 64K on-chip ROM (usually 0k to 4k)
– max of 64K external data memory
– max of 64K external code memory
– 2 timers, one serial port
– 128 bytes of on-chip RAM
– various speeds from 12MHz
Clones may have different on-chip memory, timers etc

18. Pin Description of the 8051
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
RST
(RXD)P3.0
(TXD)P3.1
(T0)P3.4
(T1)P3.5
XTAL2
XTAL1
GND
(INT0)P3.2
(INT1)P3.3
(RD)P3.7
(WR)P3.6
Vcc
P0.0(AD0
)P0.1(AD1)
P0.2(AD2
)P0.3(AD3)
P0.4(AD4)
P0.5(AD5)
P0.6(AD6)
P0.7(AD7)
EA/VPP
ALE/PROG
PSEN
P2.7(A15)
P2.6(A14
)P2.5(A13
)P2.4(A12
)P2.3(A11
)P2.2(A10)
P2.1(A9)
P2.0(A8)
8051
(8031)

19. DIP40: plastic dual in-line package; 40 leads (600 mil)
The 8051 Package

20. PLCC44: plastic leaded chip carrier; 44 leads

21. LQFP44: plastic low profile quad flat package; 44 leads

22. Block Diagram
CPU
On-chip
RAM
On-chip
ROM for
program
code
4 I/O Ports
Timer 0
Serial
PortOSC
Interrupt
Control
External interrupts
Timer 1
Timer/Counter
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs

23. Registers
A
B
R0
R1
R3
R4
R2
R5
R7
R6
DPH DPL
PC
DPTR
PC
Some 8051 16-bit Register
Some 8-bitt Registers of
the 8051
=Temporary memory (storage)

24. The 8051 Programming

25. Mnemonic Operand(s) Description
ACALL addr11 Absolute subroutine call
ADD A,Rn Add register to Accumulator
ADD A,direct Add direct byte to Accumulator
ADD A,@Ri Add indirect RAM to Accumulator
ADD A,#data Add immediate data to Accumulator
ADDC A,Rn Add register to Accumulator with carry
ADDC A,direct Add direct byte to Accumulator with carry
ADDC A,@Ri Add indirect RAM to Accumulator with carry
ADDC A,#data Add immediate data to Accumulator with carry
AJMP addr11 Absolute jump
ANL A,Rn AND Register to Accumulator
ANL A,direct AND direct byte to Accumulator
ANL A,@Ri AND indirect RAM to Accumulator
ANL A,#data AND immediate data to Accumulator
ANL direct,A AND Accumulator to direct byte
ANL direct,#data AND immediate data to direct byte
ANL C,bit AND direct bit to carry
ANL C,/bit AND complement of direct bit to carry
CJNE A,direct,rel Compare direct byte to Acc and jump if not equal
CJNE A,#data,rel Compare immediate to Acc and jump if not equal
CJNE RN,#data,rel Compare immediate to register and jump if not equal
CJNE @Ri,#data,rel Compare immediate to indirect and jump if not equal
CLR A Clear Accumulator
CLR C Clear carry
CLR bit Clear direct bit
CPL A Complement Accumulator
CPL C Complement carry
CPL bit Complement direct bit
DA A Decimal Adjust Accumulator
DEC A Decrement Accumulator
DEC Rn Decrement Register
DEC direct Decrement direct byte
DEC @Ri Decrement indirect RAM
DIV AB Divide A by B
DJNZ Rn,rel Decrement register and jump if not zero
DJNZ direct,rel Decrement direct byte and jump if not zero
INC A Increment Accumulator
INC Rn Increment register
INC direct Increment direct byte
INC @Ri Increment indirect RAM
INC DPTR Increment Data Pointer
JB rel Jump if direct bit is set
JBC bit,rel Jump if direct bit is set and clear bit
JC rel Jump if carry is set
JMP @A+DPTR Jump indirect relative to the DPTR
JNB rel Jump if direct bit is not set
JNC rel Jump if carry not set
JNZ rel Jump if Accumulator is not zero
JZ rel Jump if Accumulator is zero
LCALL addr16 Long subroutine call
LJMP addr16 Long jump
MOV A,Rn Move register to Accumulator
MOV A,direct Move direct byte to Accumulator
MOV A,@Ri Move indirect RAM to Accumulator
MOV A,#data Move immediate data to Accumulator
MOV Rn,A Move Accumulator to register
MOV Rn,direct Move direct byte to register
MOV RN,#data Move immediate data to register
MOV direct,A Move Accumulator to direct byte
MOV direct,Rn Move register to direct byte
MOV direct,direct Move direct byte to direct
MOV direct,@Ri Move indirect RAM to direct byte
MOV direct,#data Move immediate data to direct byte
MOV @Ri,A Move Accumulator to indirect RAM
MOV @Ri,direct Move direct byte to indirect RAM
MOV @Ri,#data Move immediate data to indirect RAM
MOV DPTR,#data16 Load Data Pointer with a 16-bit constant
MOV C,bit Move direct bit to carry
MOV bit,C Move carry to direct bit
MOVC A,@A+DPTR Move Code byte relative to DPTR to Accumulator
MOVC A,@A+PC Move Code byte relative to PC to Accumulator
MOVX A,@Ri Move external RAM (8-bit addr) to Accumulator
MOVX A,@DPTR Move external RAM (16-bit addr) to Accumulator
MOVX A,@Ri,A Move Accumulator to external RAM (8-bit addr)
MOVX @DPTR,A Move Accumulator to external RAM (16-bit addr)
MUL AB Multiply A and B
NOP none No operation
ORL A,Rn OR register to Accumulator
ORL A,direct OR direct byte to Accumulator
ORL A,@Ri OR indirect RAM to Accumulator
ORL A,#data OR immediate data to Accumulator
ORL direct,A OR Accumulator to direct byte
ORL direct,#data OR immediate data to direct byte
ORL C,bit OR direct bit to carry
The 8051 Instruction set

26. Assembly Language programming:
• Hand assembly:
- translate manually
- key-in opcodes for instruction
- time consuming & error prone.
• Assembly language.
- use assembler program to generate
machine codes.
- easier and faster.

27. Assembly Language programming:
• address / program pointer
• opcodes
• Assembly language

28. Program Development
Stop
Create /edit
source codes
Assemble
source codes
Syntax
Errors?
Test / debug
program
Logical
Errors?
Start
Yes
Yes
No
No
Text editor
Debugger
Assembler

29. Programming is both a science and art !!
Science – rules of grammar, punctuation,
spelling & structure.
Art – how the words are arranged

30. How to tell a lump of sand what to do:
1. study common programming techniques
2. analyze example programs
3. write many practice programs

31. Structure of Assembly language and
Running an 8051 program
ORG 0H
MOV R5,#25H
MOV R7,#34H
MOV A,#0
ADD A,R5
ADD A,#12H
END
EDITOR
PROGRAM
ASSEMBLER
PROGRAM
LINKER
PROGRAM
OH
PROGRAM
Myfile.asm
Myfile.obj
Other obj file
Myfile.lst
Myfile.abs
Myfile.hex

32. Move Data
concepts:
• data is stored at a source address
moved to (actually, data is copied)
a destination address.
= Addressing modesAddressing modes.

33. Move Data
concepts:
• 24 mnemonics
for move
•MOVMOV
•MOVXMOVX
•MOVCMOVC

34. Move Data
concepts:
• 2 + 4 mnemonics for :
•PUSH & POPPUSH & POP
•XCHXCH

36. Simulation

37. Simulation

38. Simulation

39. Simulation

41. MOVMOV A,#45HA,#45H
MOVMOV A,R0A,R0
MOVMOV A,40HA,40H
MOVMOV A,@R0A,@R0
MOVC A,@A+DPTRMOVC A,@A+DPTR
Immediate Addressing
Register Addressing
Direct Addressing
Register Indirect Addressing
Indexed Addressing
Modes Examples
To summarize:To summarize:
For external memory MOVX A,R3MOVX A,R3

42. Exchange
XCH A,Rn Exchange register with Accumulator
XCH A,direct Exchange direct byte with Accumulator
XCH A,@Ri Exchange indirect RAM with Accumulator
XCHD A,@Ri Exchange low-order digit indirect RAM with Acc
Example:
XCH A,R3
XCH A,22H
XCH A,@R1
XCHD A,@R1
Simulation

43. Arithmetic & Logic

44. Arithmetic
ADD A,Rn Add register to Accumulator
ADD A,direct Add direct byte to Accumulator
ADD A,@Ri Add indirect RAM to Accumulator
ADD A,#data Add immediate data to Accumulator
ADDC A,Rn Add register to Accumulator with carry
ADDC A,direct Add direct byte to Accumulator with carry
ADDC A,@Ri Add indirect RAM to Accumulator with carry
ADDC A,#data Add immediate data to Accumulator with carry
DIV AB Divide A by B
MUL AB Multiply A and B
SUBB A,Rn Subtract Register from Accumulator with borrow
SUBB A,direct Subtract direct byte from Accumulator with borrow
SUBB A,@Ri Subtract indirect RAM from Accumulator with borrow
SUBB A,#data Subtract immediate data from Acc with borrow

45. Logic
ANL A,Rn AND Register to Accumulator
ANL A,direct AND direct byte to Accumulator
ANL A,@Ri AND indirect RAM to Accumulator
ANL A,#data AND immediate data to Accumulator
ANL direct,A AND Accumulator to direct byte
ANL direct,#data AND immediate data to direct byte
ANL C,bit AND direct bit to carry
ANL C,/bit AND complement of direct bit to carry
ORL A,Rn OR register to Accumulator
ORL A,direct OR direct byte to Accumulator
ORL A,@Ri OR indirect RAM to Accumulator
ORL A,#data OR immediate data to Accumulator
ORL direct,A OR Accumulator to direct byte
ORL direct,#data OR immediate data to direct byte
ORL C,bit OR direct bit to carry
ORL C,/bit OR complement of direct bit to carry

46. Logic
XRL A,Rn Exclusive-OR register to Accumulator
XRL A,direct Exclusive-OR direct byte to Accumulator
XRL A,@Ri Exclusive-OR indirect RAM to Accumulator
XRL A,#data Exclusive-OR immediate data to Accumulator
XRL direct,A Exclusive-OR Accumulator to direct byte
XRL direct,#data Exclusive-OR immediate data to direct byte
Example: ANL A,1AH
ANL 22H,#11H
ORL A,R1
ORL A,@R1
XRL A,4FH
XRL 2AH,#AAH
Simulation

47. ADD A, Source ;A=A+SOURCE
ADD A,#6 ;A=A+6
ADD A,R6 ;A=A+R6
ADD A,6 ;A=A+[6] or A=A+R6
ADD A,0F3H ;A=A+[0F3H]

48. SETB bit ; bit=1
CLR bit ; bit=0
SETB C ; CY=1
SETB P0.0 ;bit 0 from port 0 =1
SETB P3.7 ;bit 7 from port 3 =1
SETB ACC.2 ;bit 2 from ACCUMULATOR =1
SETB 05 ;set high D5 of RAM loc. 20h
Note:
CLR instruction is as same as SETB
i.e:
CLR C ;CY=0
But following instruction is only for CLR:
CLR A ;A=0
Bit Addressable
Page 359,360

49. SUBB A,source ;A=A-source-CY
SETB C ;CY=1
SUBB A,R5 ;A=A-R5-1
ADC A,source ;A=A+source+CY
SETB C ;CY=1
ADC A,R5 ;A=A+R5+1

50. DEC byte ;byte=byte-1
INC byte ;byte=byte+1
INC R7
DEC A
DEC 40H ; [40]=[40]-1
CPL A ;1’s complement
Example:
MOV A,#55H ;A=01010101 B
L01: CPL A ;A=10101010 B
MOV P1,A
ACALL DELAY
SJMP L01
NOP & RET & RETI
All are like 8086 instructions.
 CALL

51. ANL - ORL - XRL
EXAMPLE:
MOV R5,#89H
ANL R5,#08H
RR – RL – RRC – RLC A
EXAMPLE:
RR A

52. Program control
instructions

53. Program Control - Jump
AJMP addr11 Absolute jump
JB rel Jump if direct bit is set
JBC bit,rel Jump if direct bit is set and clear bit
JC rel Jump if carry is set
JMP @A+DPTR Jump indirect relative to the DPTR
JNB rel Jump if direct bit is not set
JNC rel Jump if carry not set
JNZ rel Jump if Accumulator is not zero
JZ rel Jump if Accumulator is zero
LJMP addr16 Long jump
SJMP rel Short jump (relative addr)

54. Program branching instructions

55. Example:
Unconditional Jump-
LOOP MOV A,#30H
MOV R1,A
bla…bla…
AJMP LOOP
LJMPSJMP

58. 8051 Instruction Set
ACALL: Absolute Call
ADD, ADDC: Add Acc. (With Carry)
AJMP: Absolute Jump
ANL: Bitwise AND
CJNE: Compare & Jump if Not Equal
CLR: Clear Register
CPL: Complement Register
DA: Decimal Adjust
DEC: Decrement Register
DIV: Divide Accumulator by B
DJNZ: Dec. Reg. & Jump if Not Zero
INC: Increment Register
JB: Jump if Bit Set
JBC: Jump if Bit Set and Clear Bit
JC: Jump if Carry Set
JMP: Jump to Address
JNB: Jump if Bit Not Set
JNC: Jump if Carry Not Set
JNZ: Jump if Acc. Not Zero
JZ: Jump if Accumulator Zero
LCALL: Long Call
LJMP: Long Jump
MOV: Move Memory
MOVC: Move Code Memory
MOVX: Move Extended Memory
MUL: Multiply Accumulator by B
NOP: No Operation
ORL: Bitwise OR
POP: Pop Value From Stack
PUSH: Push Value Onto Stack
RET: Return From Subroutine
RETI: Return From Interrupt
RL: Rotate Accumulator Left
RLC: Rotate Acc. Left Through Carry
RR: Rotate Accumulator Right
RRC: Rotate Acc. Right Through Carry
SETB: Set Bit
SJMP: Short Jump
SUBB: Sub. From Acc. With Borrow
SWAP: Swap Accumulator Nibbles
XCH: Exchange Bytes
XCHD: Exchange Digits
XRL: Bitwise Exclusive OR
Undefined: Undefined Instruction

59. The 8051 I/O
programming

60. ABITEC Application Board programming:
1. Eight large LED arrays
2. Eight switches array
3. Two Dual seven segment displays
4. DC Motor & Control
5. Semiconductor temperature sensor
6. Speaker
7. Heater control circuit
8. Telephone type keypad matrix
9. Fibre optic transmitter and receiver
10. Slider potentiometer - variable analogue voltage
11. An 8 bit Digital to Analogue Converter (DAC) and
comparator to enable programming of ADC functions
• Optional:
• LCD interface
• Stepper Motor Control (D4 - D7)

62. Time Delay
•To write accurate time delay routine.
•Using the DJNZ or CJNE instruction.

64. Interrupts
1. Enabling and Disabling Interrupts
2. Interrupt Priority
3. Writing the ISR (Interrupt Service
Routine)

65. Interrupt Enable (IE) Register :
• EA : Global enable/disable.
• --- : Undefined.
• ET2 :Enable Timer 2 interrupt.
• ES :Enable Serial port interrupt.
• ET1 :Enable Timer 1 interrupt.
• EX1 :Enable External 1 interrupt.
• ET0 : Enable Timer 0 interrupt.
• EX0 : Enable External 0 interrupt.

66. Interrupt Vectors
Interrupt Vector Address
System Reset 0000H
External 0 0003H
Timer 0 000BH
External 1 0013H
Timer 1 001BH
Serial Port 0023H
Timer 2 002BH

67. Writing the ISR
Example:
Writing the ISR for Timer0 interrupt
ORG 0000H ;reset
LJMP MAIN
ORG 000BH ;Timer0 entry point
T0ISR: . ;Timer0 ISR begins
.
RETI ;return to main program
MAIN: . ;main program
.
.
END