AN3275 Bootloader Problem

[cokezero]

I must be missing something, because the serial bootloader is causing bizarre behaviour on my HCS12 dev board:

I have a very simple test app that toggles pins on PORTB (MCS12DG256).  The code compiles and runs as expected when flashed via the BDM.  However after flashing the code through a serial bootloader (unmodified AN3275), PORTB does not respond to output commands.

I code appears to be flashed properly, and the bootloader successfully switches to the app start location.  I have tested other ports and the serial connection, which all seem to be working fine. The problem for now appears isolated to PORTAB.

Is there anything that the AN3275 bootloader would do to affect PORTAB in a flashed application?

Thanks!

[cokezero · Accepted solution]

Solved.

It turns out that the bootloader code I was using had been modified (a lesson on the importance of rev control!), causing the chip to boot in expanded mode which then overloaded the PORTB pins on the dev board. Booting in single chip mode seems to have solved the problem.