AT89C55WD Atmel Corporation, AT89C55WD Datasheet - Page 22

• Manufacturer Part Number: AT89C55WD
• Manufacturer: Atmel Corporation

Specifications of AT89C55WD

• Flash (kbytes): 20 Kbytes
• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Uart: 1
• Sram (kbytes): 0.25
• Operating Voltage (vcc): 4.0 to 6.0
• Timers: 3
• Watchdog: Yes

Table 21-1.
Notes:
22
Mode
Write Code
Data
Read Code
Data
Write Lock Bit
1
Write Lock Bit
2
Write Lock Bit
3
Read Lock Bits
1, 2, 3
Chip Erase
Read Atmel ID
Read Device
ID
Read Device
ID
1. Write Code Data requires a 200 ns PROG pulse.
2. Write Lock Bits requires a 100 µs PROG pulse.
3. Chip Erase requires a 200 ns - 500 ns PROG pulse.
4. RDY/BSY signal is output on P3.0 during programming.
AT89C55WD
Flash Programming Modes
V
6.5
6.5
6.5
6.5
5V
5V
5V
5V
5V
5V
CC
V
V
V
V
RST
H
H
H
H
H
H
H
H
H
H
PSEN
L
L
L
L
L
L
L
L
L
L
PROG
ALE/
H
H
H
H
H
(1)
(2)
(2)
(2)
(3)
H/12V
EA/
V
12V
12V
12V
12V
12V
H
H
H
H
PP
P2.6
H
H
H
H
H
L
L
L
L
L
P2.7
H
H
H
H
L
L
L
L
L
L
P3.3
H
H
H
H
H
L
L
L
L
L
P3.6
H
H
H
H
H
L
L
L
L
L
P3.7
H
H
H
L
L
L
L
L
L
L
P0.7-0
Data
P0.2,
P0.3,
D
P0.4
1EH
55H
06H
D
OUT
X
X
X
X
IN
P3.4
A14
A14
X
X
X
X
X
X
X
X
XX 0000
XX 0001
XX 0010
Address
P2.5-0
A13-8
A13-8
1921D–MICRO–6/08
X
X
X
X
X
P1.7-0
A7-0
A7-0
00H
00H
00H
X
X
X
X
X