AT89LP51 Atmel Corporation, AT89LP51 Datasheet - Page 75

• Manufacturer Part Number: AT89LP51
• Manufacturer: Atmel Corporation

Specifications of AT89LP51

• Flash (kbytes): 4 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 36
• Uart: 1
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 3
• Isp: SPI
• Watchdog: Yes

16. Instruction Set Summary
3709D–MICRO–12/11
The AT89LP51/52 is fully binary compatible with the 8051 instruction set. In Compatibility mode
the AT89LP51/52 has identical execution time with AT89S51/52 and other standard 8051s. The
difference between the AT89LP51/52 in Fast mode and the standard 8051 is the number of
cycles required to execute an instruction. Fast mode instructions may take 1 to 5 clock cycles to
complete. The execution times of most instructions may be computed using
that for the purposes of this table, a clock cycle is one period of the output of the system clock
divider. For Fast mode the divider defaults to 1, so the clock cycle equals the oscillator period.
For Compatibility mode the divider defaults to 2, so the clock cycle is twice the oscillator period,
or conversely the clock count is half the number of oscillator periods.
Table 16-1.
Generic Instruction Types
Most arithmetic, logical, bit and transfer instructions
Branches and Calls
Single Byte Indirect (i.e. ADD A, @Ri, etc.)
RET, RETI
MOVC
MOVX
MUL
DIV
INC DPTR
Arithmetic
ADD A, Rn
ADD A, direct
ADD A, @Ri
ADD A, #data
ADDC A, Rn
ADDC A, direct
ADDC A, @Ri
ADDC A, #data
SUBB A, Rn
SUBB A, direct
SUBB A, @Ri
SUBB A, #data
INC Rn
INC direct
INC @Ri
INC A
DEC Rn
DEC direct
Instruction Execution Times and Exceptions
Bytes
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
1
2
Compatibility
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
(1)
Clock Cycles
Fast Mode Cycle Count Formula
Fast
AT89LP51/52
1
2
2
2
1
2
2
2
1
2
2
2
1
2
2
2
1
2
# bytes + 1
# bytes
4
Table
2
4
3
2
4
2
(3)
Hex Code
16-1. Note
28-2F
38-3F
98-9F
08-0F
18-1F
26-27
36-37
96-97
06-07
25
24
35
34
95
94
05
04
15
75