AT89C4051-12PA View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT89C4051-12PA

8-Bit Microcontroller with 4K Bytes Flash

Atmel Corporation 

AT89C4051

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.

(000H) = 1EH indicates manufactured by Atmel

(001H) = 41H indicates 89C4051

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.

Flash Programming Modes

Mode

Write Code Data(1)(3)

RST/VPP

12V

P3.2/PROG

P3.3

L

P3.4

H

P3.5

H

P3.7

H

Read Code Data(1)

Write Lock

H

Bit - 1

12V

H

L

L

H

H

H

H

H

H

Bit - 2

12V

H

H

L

L

Chip Erase

12V

(2)

H

L

L

L

Read Signature Byte

H

H

L

L

L

L

Notes: 1. The internal PEROM address counter is reset to 000H on the rising edge of RST and is advanced by a positive pulse at

XTAL 1 pin.

2. Chip Erase requires a 10-ms PROG pulse.

3. P3.1 is pulled Low during programming to indicate RDY/BSY.

7

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