at89c4051-12sa ATMEL Corporation, at89c4051-12sa Datasheet - Page 7

• Manufacturer Part Number: at89c4051-12sa
• Description: 8-bit Microcontroller With 4k Bytes Flash
• Manufacturer: ATMEL Corporation

Reading the Signature Bytes: The signature bytes are
read by the same procedure as a normal verification of
locations 000H, 001H, and 002H, except that P3.5 and
P3.7 must be pulled to a logic low. The values returned are
as follows.
Flash Programming Modes
Notes:
Mode
Write Code Data
Read Code Data
Write Lock
Chip Erase
Read Signature Byte
(000H) = 1EH indicates manufactured by Atmel
(001H) = 41H indicates 89C4051
1. The internal PEROM address counter is reset to 000H on the rising edge of RST and is advanced by a positive pulse at
2. Chip Erase requires a 10-ms PROG pulse.
3. P3.1 is pulled Low during programming to indicate RDY/BSY.
XTAL 1 pin.
(1)(3)
(1)
Bit - 1
Bit - 2
RST/VPP
12V
12V
12V
12V
H
H
Programming Interface
Every code byte in the Flash array can be written and the
entire array can be erased by using the appropriate combi-
nation of control signals. The write operation cycle is self-
timed and once initiated, will automatically time itself to
completion.
All major programming vendors offer worldwide support for
the Atmel microcontroller series. Please contact your local
programming vendor for the appropriate software revision.
P3.2/PROG
H
H
(2)
P3.3
H
H
H
L
L
L
P3.4
H
H
H
L
L
L
P3.5
H
H
H
L
L
L
P3.7
H
H
H
L
L
L
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