AT89LP51ED2-20JU Atmel, AT89LP51ED2-20JU Datasheet - Page 180

• Manufacturer Part Number: AT89LP51ED2-20JU
• Description: 8-bit Microcontrollers - MCU 64KB 20MHz 2.4V-5.5V
• Manufacturer: Atmel

Specifications of AT89LP51ED2-20JU

• Rohs: yes
• Core: 8051
• Processor Series: AT89x
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Program Memory Size: 64 KB
• Data Ram Size: 256 B
• On-chip Adc: Yes
• Operating Supply Voltage: 2.4 V to 5.5 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: PLCC-44
• Mounting Style: SMD/SMT
• Data Rom Size: 4 KB
• Interface Type: 2-Wire, SPI, UART
• Number Of Programmable I/os: 36
• Number Of Timers: 3
• Program Memory Type: Flash
• Factory Pack Quantity: 27

22.1.3
22.1.4
180
Description: CJNE compares the magnitudes of the Accumulator and indirect RAM location and branches if their values are
Description: CLR M clears the 40-bit M register. No flags are affected.
Operation: CJNE
Operation: JMP
Encoding:
Encoding:
AT89LP51RD2/ED2/ID2 Preliminary
Function: Compare and Jump if Not Equal
Function: Clear MAC Accumulator
CJNE A, @R
CLR M
Example: The Accumulator contains 34H. Register 0 contains 78H and 78H contains 56H. The first instruction in the
Example: The M registercontains 123456789AH. The following instruction,
Cycles: 9
Cycles: 2
Bytes: 2
Bytes: 2
not equal. The branch destination is computed by adding the signed relative-displacement in the last instruction
byte to the PC, after incrementing the PC to the start of the next instruction. The carry flag is set if the unsigned
integer value of ACC is less than the unsigned integer value of the indirect location; otherwise, the carry is
cleared. Neither operand is affected.
sequence,
;
NOT_EQ:
;
sets the carry flag and branches to the instruction at label NOT_EQ. By testing the carry flag, the second
instruction determines whether ACC is greater or less than the location pointed to by R0.
(PC) ← (PC) + 3
IF (A) ≠ ((R
THEN
IF (A) < ((R
THEN
ELSE
CLR M
leaves the M register set to 0000000000H.
(M) ← 0
i
, rel
A5
A5
CJNE
(PC) ← (PC) + relative offset
(C) ← 1
(C) ← 0
JC
. . . . . .
. . . . . .
i
i
))
))
A, @R0, NOT_EQ
REQ_LOW .. ;IF ACC< @R0.
...... ...... ; ACC = @R0.
...... ...... ;ACC > @R0.
1
1
0
1
1
1
1
0
0
0
1
1
1
0
0
i
rel. address
3714A–MICRO–7/11