Koen Teetaert

HCS12 external bus problems

Discussion created by Koen Teetaert on Oct 4, 2006
Latest reply on Oct 12, 2006 by William Whyte
Hi all,
 
I'm trying to let the external databus work on my 9S12S256 device, but it doesn't work.
I want to acces external data in the paged bank. 8000 - C000 on PPAGE 0.
 
After start-up I set the mode register directly
MODE = 0xE0;
PEAR = 0x0C;
MISC = 0x01;
EBICTL = 0x00;
 
With this settings, the bus doesn't work. When I measure with the scoop, my clock seems to be OK. I don't see a R/W pulse.
My function is running in the common bank 0xC000 - 0xFFFF.
 
Ideas?
 
Thanks
 
Koen
 
 

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