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

[Scott and Roxanne Munns]

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