9

0368G–MICRO–6/05

AT89C2051

12. Programming Interface

Every code byte in the Flash array can be written and the entire array can be erased by using

the appropriate combination of control signals. The write operation cycle is self-timed and once

initiated, will automatically time itself to completion.

Most major worldwide programming vendors offer support for the Atmel AT89 microcontroller

series. Please contact your local programming vendor for the appropriate software revision.

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

XTAL1 pin.

2. Chip Erase requires a 10 ms PROG pulse.

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

13. Flash Programming Modes

Mode

RST/VPP

P3.2/PROG

P3.3

P3.4

P3.5

P3.7

Write Code Data

(1)(3)

12V

L

H

H

H

Read Code Data

(1)

HH

L

L

H

H

Write Lock

Bit - 1

12V

HH

HH

Bit - 2

12V

H

H

L

L

Chip Erase

12V

H

L

L

L

Read Signature Byte

H

H

L

L

L

L

(2)