Hi
I played with tthe MM to audio conversion a bit today. I NEED HELP!!
Should 74ls139 pin 8 be grounded? (YES)
I build it with a 32k sram grounding the 2 extra adresslines (what a waste, but I have them in ample supply old 286/386 motherboards) It did not work Running SUPPER-X I found the sram mapped & mirrored to 0000,2000,4000,6000,8000,A000. Sram is stable I could not read anything else (see the eprom)( 1000, 3000 etc is FF)
I switched the CS (CE) signals!
27C256 pin 20 to 74LS139 pin 11
61256 pin 20 to 74LS139 pin 12
Now Sram is mapped & Mirrored to 1000, 3000, 5000, 7000, 9000, B000
Sram is stable
I do read data on (0000,2000,8000, A000),(4000,6000) () mirrored inside the pair
Call Audio still does not work.
I know the mirroring of the eprom can be due to the mappertype and super-x readig it unmapped
What is wrong??
JP
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