[MSX] MSX-Audio BIOS upgrade for Music Module

[JP Grobler]

 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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