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

[VZLJOT]

Hello

Thursday, August 7, 2003, 6:03:06 AM, you wrote:

Scott and Roxanne Munns> Greetings everyone,

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

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

Scott and Roxanne Munns> Has anyone run into similar problems?  Any 
suggestions, solutions, or things
Scott and Roxanne Munns> to check into?

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

I have similar problems but with interrupt processing. In
compatible mode Mega128 don't clear some interrupt flags as
Mega103 does. So I put in interrupt subroutines forced
clearing of those flags. The hardware was the same.

-- 
Best regards
Lev Vyskubov               mailto:address@hidden