AT89C51ED2-RDTIM datasheet(106/137 Pages) ATMEL

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106

AT89C51RD2/ED2

4235E–8051–04/04

Full Chip Erase

The ISP command "Full Chip Erase" erases all user Flash memory (fills with FFh) and

sets some bytes used by the bootloader at their default values:

•

BSB = FFh

•

SBV = FCh

•

SSB = FFh

The Full Chip Erase does not affect the bootloader.

Checksum Error

When a checksum error is detected, send ‘X’ followed with CR&LF.

Flow Description

Overview

An initialization step must be performed after each Reset. After microcontroller reset,

the bootloader waits for an autobaud sequence (see section ‘Autobaud Performances’).

When the communication is initialized, the protocol depends on the record type

requested by the host.

FLIP, a software utility to implement ISP programming with a PC, is available from the

Atmel web site.

Communication Initialization

The host initializes the communication by sending a ’U’ character to help the bootloader

to compute the baudrate (autobaud).

Figure 46. Initialization

Host

Bootloader

"U"

Performs Autobaud

Init Communication

If (Not Received "U")

"U"

Communication Opened

Else

Sends Back “U” Character

AT89C51ED2-RDTIM 数据表(PDF) 106 Page - ATMEL Corporation

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