Datasheet

5
4266C–CAN–03/08
AT89C51CC03 UART Bootloader
FLIP Software
Program
FLIP is a PC software program running under Windows 9x / NT / 2K / XP and LINUX that sup-
ports all Atmel C51 Flash microcontrollers.
This free software program is available on the Atmel web site.
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 the higher level protocol over the
serial line.
Boot Process The bootloader can be activated in two ways:
• Hardware conditions
• Regular boot process
Hardware Condition The Hardware conditions (EA = 1, PSEN = 0) during the RESET# falling edge force the on-chip
bootloader execution. In this way the bootloader can be carried out whatever the user Flash
memory content.
As PSEN is an output port in normal operating mode (running user application or bootloader
code) after reset, it is recommended to release PSEN after falling edge of reset signal. The hard-
ware conditions are sampled at reset signal falling edge, thus they can be released at any time
when reset input is low.