1997 F-Body Tools

[Tom H]

Hi,

This morning I tested the idea of reprogramming the EEPROM to hold some sort of non-volatile loader while programming. This *should* prevent making bricks even if the power is removed half way or some other interruption occurs.

This can be done in this way, there are just a few steps:

1. Record the content of EEPROM. This has been done in the software I am currently writing.
2. Run the code below to keep BPROT bits clear. This will no permit you to reload the CONFIG register and place the EEPROM at the top of page overlapping the flash.
3. Run code to program (not written yet) the EEPROM with a boot loader in case of programming interruption.
4. Turn off the EEPROM while programming to permit access to the top of FLASH.
5. When programming is complete, restore the EEPROM, reset the CONFIG register as normal

Once this is done, the code will always run the code in EEPROM, not the regular stuff in flash. At that point you can load into ram the programming and comms routines.

        ORG $0000

ENTRY:    LDAA    #$55        ; TAG VALUE
          STAA    $0200        ; SAVE
SLOOP:    BRA    SLOOP        ; SUICIDE BY COP

Thoughts?

-Tom