AT89LS8252_ 查看數據表（PDF） - Atmel Corporation

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AT89LS8252_

Microcontrollers

Atmel Corporation 

This errata sheet is applicable to the following devices:

• AT89S8252

• AT89LS8252

Problem

In revisions “S” and earlier of the AT89S8252 and AT89LS8252 devices, inadvertent

writes to either the Flash program memory or the data EEPROM memory can occur.

An inadvertent write is a possibility in the following two scenarios.

Case A Conditions

1. A MOVX instruction is used to write to the internal EEPROM.

2. P2.4 = 0 (driven by external hardware)

P2.5 = 1

3. The RST pin is asserted high during execution of any MOVX instruction that

writes to the EEPROM, while VCC is on.

In this case, an inadvertent write to the EEPROM address location corresponding to

the value at Port 1 and pins P2.0 - P2.5 can occur.

Case B Conditions

1. A MOVX instruction is used to write to the internal EEPROM.

2. P2.4 = 0 (driven by external hardware)

P2.5 = 0 (driven by external hardware)

3. The RST pin is asserted high during execution of any MOVX instruction that

writes to the EEPROM, while VCC is on.

In this case, an inadvertent write to the Flash memory address location corresponding

to the value at Port 1 and pins P2.0 - P2.5 can occur.

Microcontrollers

AT89S8252

AT89LS8252

Errata Sheet

Solutions

1. Avoid driving pins P2.4 and P2.5 to logic level “0” by external hardware before

performing a “warm” (soft) reset.

2. Use revision “T” or later of the devices involved.

Rev. 1963A–10/00

1

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