Connect AY-3-8910 sound chip to FME-7 board

[Banshaku]

It's around 20$ in japan at cybergadget:

I may buy one someday but for some reason they sell it at an exorbitant price on amazon.jp so I don't know if it's means it's discontinued or not.

[Ben Boldt]

It's around 20$ in japan at cybergadget:

4544859022630.jpg

I may buy one someday but for some reason they sell it at an exorbitant price on amazon.jp so I don't know if it's means it's discontinued or not.

I like it, it looks very nice. It is nice that it is keyed on both sides so nothing can go backwards. I have put a cart in backwards once by accident. Amazingly nothing broke.

[Haruka]

I have a question about the circuit.

Why connect PRG A14 and PRG A13 to 74'139 and AY-3-8910, rather than CPU A14 and CPU A13? We are trying to decode CPU memory region $C000~$FFFF, not PRG, aren't we?
Connecting PRG /CE rather than CPU /ROMSEL to 74'139 is also confusing me.

I found that what we are trying to do is quite similar with PRG RAM circuit. The sole difference is the address region. Am I correct?

[krzysiobal]

It is CPU, not PRG, as you correctly think.

[Haruka]

It is CPU, not PRG, as you correctly think.

So this is the "not so confusing" circuit, right?

Code: Select all

          74'139
         -----v-----
     GND-|/1E   VCC|-+5V
139./2Y1-|1A    /2E|-CPU /ROMSEL
139./2Y1-|1B     2A|-CPU A14
        -|/1Y0   2B|-CPU R/W
        -|/1Y1 /2Y0|-
        -|/1Y2 /2Y1|-139.1A
 AY.BDIR-|/1Y3 /2Y2|-
     GND-|GND  /2Y3|-
         -----------

AY-3-8910
----v----
    .   |
    .   |
    .   |
     BC1|-GND
     BC2|-CPU A13
    BDIR|-139./1Y3
    .   |
    .   |
    .   |
---------

[krzysiobal]

Yep, and 8910.A8=VCC, 8910./A9=GND, 8910.CLK=M2 divided by 2

[Haruka]

Yep, and 8910.A8=VCC, 8910./A9=GND, 8910.CLK=M2 divided by 2

Thank you krzysiobal! I'll try making my reproduction.