Телеграмм чат группы proembedded страница 12283

maybe your cpu faulty?

07:26пожаловаться #1

Anton Kirilenko

maybe your cpu faulty?

yes thats my guess too. I'm not so familiar with this system. I even don't know what happend to this chess computer. Mask ROM dead, oscillator circuit was dead. I had to switch some parts to get the clock signal working. I replaced the U2364 mask rom with 2764 or 27256 EPROM. But something other is wrong and i have to find out what exactly.

07:29пожаловаться #2

or you can try to use ADD A,0 or OR A instead of NOP

07:30пожаловаться #3

it's an old chess master diamond from 1988, Made in GDR. Some russian parts are inside.

07:31пожаловаться #4

afaik, they can use U880, not original z80

07:32пожаловаться #5

Anton Kirilenko

or you can try to use ADD A,0 or OR A instead of NOP

i was looking for such a code to test the RAM. Write to each cell and read it back to check if RAM is working. But assembly is hard for me.

07:32пожаловаться #6

it's a U880

07:33пожаловаться #7

i guess :))))

07:33пожаловаться #8

try original Z80

07:33пожаловаться #9

or burn ROM with LD A,A (#7f) instruction and trace

07:34пожаловаться #10

yes, i ordered one and RAM parts too. Would be easier to find out by testing than by switching parts. Board quality is not that good. So every part i replace it's a risk.

07:35пожаловаться #11

Anton Kirilenko

or burn ROM with LD A,A (#7f) instruction and trace

how can i do this for the whole ram? RAM starts at 8000, its 6x 4kbit U224

07:37пожаловаться #12

exclude ram from address space