AT89C55WD Atmel Corporation, AT89C55WD Datasheet - Page 23

• 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

1921D–MICRO–6/08
Figure 21-1. Programming the Flash Memory
Figure 21-2. Verifying the Flash Memory
Note:
*Programming address line A14 (P3.4) is not the same as the external memory address line A14
(P2.6).
3 - 33 MHz
3 - 33 MHz
PROGRAMMING
MODES TABLE
PROGRAMMING
MODES TABLE
SEE FLASH
0000H/4FFFH
0000H/4FFFH
SEE FLASH
ADDR.
ADDR.
A14*
A14*
A0 - A7
A0 - A7
A8 - A13
A8 - A13
P3.3
P1.0 - P1.7
P2.0 - P2.5
P3.4
P2.6
P2.7
P3.6
P3.7
XTAL2
XTAL1
GND
P1.0 - P1.7
P2.0 - P2.5
P3.4
P2.6
P2.7
P3.3
P3.6
P3.7
XTAL 2
XTAL1
GND
AT89C55WD
AT89C55WD
PSEN
PSEN
P3.0
RST
ALE
V
RST
ALE
EA
P0
V
CC
EA
P0
CC
4.5V to 5.5V
4.5V to 5.5V
PGM DATA
(USE 10K
PULL-UPS)
PGM
DATA
PROG
V /V
V
RDY/
BSY
V
IH
IH
V
IH
IH
PP
AT89C55WD
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