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4223C–CAN–03/08

T89C51CC02 UART Bootloader

In-System

Programming

The ISP allows the user to program or reprogram a microcontroller’s on-chip Flash memory

through the serial line without removing it from the system and without the need of a pre-pro-

grammed application.

This section describes how to start the UART bootloader and all higher level protocol over the

serial line.

Boot Process

The bootloader can be activated in two ways:

•

Hardware condition

•

Regular boot process

Hardware Condition

The Hardware Condition forces the bootloader execution from reset.

The default factory Hardware Condition is assigned to port P1.

•

P1 must be equal to FEh

In order to offer the best flexibility, the user can define its own Hardware Condition on one of this

following Port:

•

Port1

•

Port3

•

Port4 (only bit0 and bit1)

The Hardware Condition configuration are stored in three bytes called P1_CF, P3_CF, P4_CF.

These bytes can be modified by the user through a set of API or through an ISP command.

There is a priority between P1_CF, P3_CF and P4_CF (see boot process diagram).

Note:

The BLJB must ba at 0 (programmed) to be able to restart the bootloader.

If the BLJB is equal to 1 (unprogrammed) only the hardware parallel programmer can change this

bit (see T89C51CC02 Datasheet for more detail).