8051 Architectural Specification and Functional Description
•DIRECT Adchuing
-Opet'llnd
RAM (I11III
•REGISTER Addressing
Operand
C
A
R7oRO
DPTR
•
-Opet'llnd
@R1. @RO [I•••• RAM
Note, SFR =Special Funcllon Regia'"
OperaUon
SETB.CLR.CPL
INC. DEC
Operation
SETB.CLR.CPL INC. DEC. DA, CLR. CPL. RL, RLC. RR. RRC.
SWAP INC. DEC INC
Operation
INC. DEC
• | Operation | |
Operand 1 | Operand 2 | |
@R1, @RO[RAM | RAM or SFA | MOV |
@SP [RAM | RAM or SFR | PUSH. POP |
• | Operation | |
Operand 1 | Opera~2 | |
@R1, @RO [RAM | A | MOV |
@R1. @RO [EXT DATA | A | MOYX |
@DPTR[EXT | A | MOYX |
• | Operation | |
Operand 1 | Opera~ 2 | |
@R1, @RO [RAM | PM (immediate) | MOV |
Figure 2.33.C. Operand Addressing Single-Operand Operations
•DIRECT, DIRECT Ad~g
- Opet'llnd1 | Operand 2 | Operation |
RAM or SFA | RAM or SFA | MOV |
•DIRECT. REGISTER Adchuing
Opet'llnd1 | OperMCI 2 | Operation |
RAM (I11III) or SFR (bI") | C | MOV. ANL, ORL |
C~RAM(IIIIII) | C | ANL,ORL |
or SFR (I11III1 |
|
|
RAMorSFA | A | . MOV. ANL, ORL, XRL |
RAM or SFR | MOV |
•DIRECT.
- Operand 1 | - Operand 2 | Operation |
RAM or SFR | @R1. @RD | MOV |
•DIRECT. IMMEDIATE Addressing
- Opmmd1 | OperMCl2 | Operation |
RAM or SFA | PM (ImmedI"') | MOV, ANL, ORL, XRL |
Note: PM = Progr.... M....ory |
|
|
Figure 2.33.F. Operand Addressing Two-Operand Operations
• REGISTER,
Operand 1 | Operand 2 • | - | Operand 3 | . Opsrmlon |
A | @ DPTR+A |
| MOVC | |
A | @PC+A |
|
| MOVC |
PC | @ DPTR+A |
| JMP (IndINcI) | |
• REGISTER. IMMEDIATE, | OperatIon | |||
- Operand 1 - | Operand 2 | - | Operand 3 | |
PC | PM (Immediate) |
| @SP | LCALL, |
|
|
|
| ACALL |
• REGISTER, IMMEDIATE, DIRECT AcIdeuIng |
| |||
Oper~ 1 | Operand 2 |
| Operand 3 | Opsrmlon |
PC | PM |
| RAM (I11III) or | JB,JNB, |
|
|
| SFR(IIIIII) | JBC |
PC | PM |
| RAM • SFA | DJNZ |
• REGISTER, IMMEDIATE, REGISTER Addrasling |
| |||
Operand' | Operand 2 |
| Operand 3 | 0 |
PC | PM |
| C | JC,JNC |
PC | PM |
| A | JZ.JNZ |
PC | PM |
| DJNZ | |
Figure 2.33.D. Operand Addressing | Figure 2.33.G. Operand Addressin'g |
|
|
• REGISTER, DIRECT Addressing
Operand 1 | Operand 2 |
CRAM (bils) or SFR (bl")
ARAMorSFR
RAM or SFR |
• REGISTER, REGISTER Addressing
Operand 1 Operand 2
AR7-RD
R7-RO A
AB
•REGISTER,
Operand 1 | Operand 2 |
A | @R1, @RO [RAM |
A@Rl,@RO [EXT DATA
A | @OPTR [EXT DATA |
PC | @SP[RAM |
• REGISTER, IMMEDIATE Addressing | |
Operand 1 | Operand 2 |
A | PM (Immedlale) |
PM (Immediate) | |
DPTR | PM (Immedlale) |
PC | PM (Immediate) |
Note: PM =Program Memory
Operalion
MOV
MOV, XCH. ADD, ADDC, SUBB,JI.NL,
ORL, XRL MOV
Operation
MOV, XCH, ADD, ADDC, SUBB,ANL,
ORL. XRL MOV MUL,DIV
Operation
MOV, XCH, ADD, ADDC, SUBB, ANL.
ORL, XRL, XCHD MOVX
MOVX
RET, RETI
Operation
MOV, ADD, ADDC, SUBB, ANL, ORL,
XRL
MOV
MOV WMP,AJMP,
SJMP
• REGISTER, IMMEDIATe, REGISTER. DIRECT AcIdnuIng |
| |||
- Operand 1 | - Operand 2 | - Operand 3 | - Operand 4 | - Operation |
PC | PM | A | RAM or SFA | CJNE |
• REGISTER. IMMEDIATE. REGISTER. IMMEDIATE Addressing
-Operand 1 - Operand 2 - Oper~ 3 - Operand 4 - Operation
PC | PM | A | PM | CJNE |
PC | PM | PM | CJNE | |
• REGISTER, IMMEDIATE, | ||||
- Operand 1 | - Operand 2 | - Operand 3 | - Operand 4 | - Operation |
PC | PM | @R1. @RO | PM | CJNE |
Figure 2.33.H. Operand AddreSSing FourmOperand Operations
2.8 INTERRUPT SYSTEM
Interrupts result in a transfer of control to a new program location. The program servicing the request begins at this address. In the 8051 there are five hardware resources that can generate an interrupt request. The starting address of the interrupt service program for each interrupt source is shown in Figure 2.34.
Figure 2.33.E. Operand Addressing Two-Operand Operations
A resource requests an interrupt by setting its associated interrupt request flag in the TCON or SCON register, as detailed in Figure 2.35. The interrupt request will be
22
