Virgil Reichert

How do I preserve Factory Trim values when programming? - MC9S08QG8

Discussion created by Virgil Reichert on Jul 17, 2008
Latest reply on Jul 24, 2008 by Jim Donelson
Hi folks:
This is my first Freescale project, so it's been a learning experience.
I wrote my program in Codewarrior 5.1 (that came with the demo board)
and tested it on the DEMO board for the MC9S08QG8, and it downloads
and runs OK.
Then I made a batch of boards with the MC9S08QG8 on it, and used the
BDM pod to download the same code to my target board.  The code got
there OK, but I realized the running frequency was wrong because the
Serial Port was spitting out garbage.
I'm using the ICS to use less parts.
So when I figured out that I overwrote the 2 bytes for the Factory Trim values
(0xFFAE, 0xFFAF), I re-wrote them with various values until my running
frequency was once again 16.0MHz and the Serial Port worked fine.
So after that long do I program more boards, this time
preserving the factory trim value?
Thanks in advance.
Added p/n to subject.

Message Edited by NLFSJ on 2008-07-18 09:13 AM