at89c55-12qi ATMEL Corporation, at89c55-12qi Datasheet - Page 15

• Manufacturer Part Number: at89c55-12qi
• Description: 8-bit Microcontroller With Bytes Flash
• Manufacturer: ATMEL Corporation

Flash Programming Modes
Notes: 1. The signature byte at location 032H designates
Mode
Read Signature Byte
Write Lock Bit - 1
Read Code Data
Write Code Data
whether V
enable programming.
Chip Erase
Bit - 2
Bit - 3
PP
= 12V or V
RST
H
H
H
H
H
H
H
PP
= 5V should be used to
PSEN
L
L
L
L
L
L
L
H
H
PROG
ALE/
(2)
H/12V
2. Chip Erase requires a 10 ms PROG pulse.
H/12V
H/12V
H/12V
H/12V
V
EA/
H
H
PP
(1)
P2.6
H
H
H
H
L
L
L
AT89C55
P2.7
H
H
H
L
L
L
L
P3.6
H
H
H
H
L
L
L
P3.7
H
H
H
L
L
L
L
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