RE: [avr-gcc-list] Difficulties switching from Mega103 to Mega128

[Rune Christensen]

Hello

Look at www.atmel.com find the document "replacing a mega103 with a mega128"

The external memory interface is changed maybe the new timings is the
problem.

Compare the datasheets from the mega103 and mega128.

Best Regards
Rune Christensen


-----Original Message-----
From: address@hidden [mailto:address@hidden
Behalf Of Scott and Roxanne Munns
Sent: Thursday, August 07, 2003 4:03 AM
To: address@hidden
Subject: [avr-gcc-list] Difficulties switching from Mega103 to Mega128


Greetings everyone,

My group at work is currently involved in converting an LCD/touchpad
controller board from the Mega103 to the Mega128.  We fully expected to be
able to drop in the new part, put the Mega128 in Mega103 compatibility mode,
and have the old software work just fine.  However, we haven't been so
fortunate.  The display shows corruption of most of the bitmaps placed on
the screen - it looks very "smudged".  The pattern isn't a fixed offset, and
it changes from time to time.

The hardware design uses the external memory interface to "memory map" the
display driver - only 2 bytes of address space used for the interface.
Preliminary analysis appears (maybe) to point at a change in the timing of
the external memory interface between the Mega128 and Mega103.

Has anyone run into similar problems?  Any suggestions, solutions, or things
to check into?

Thanks for your help (and sorry for being off-topic),
Scott Munns