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

[yxkalle]

Can I use an YMZ284 instead if I connect:

PRG A13 to A0
(NOT PRG_CE) NAND PRG_A14 to /CE (/CE goes low when PRG /CE is low AND PRG A14 is high)
PRG R/W to /WR

...and everything else like the previous versions? I'm new to this cart hacking stuff.

Thanks

[Jarhmander]

Yes, I did exactly that and it works. Interestingly, R/W doesn't really work on this chip and it is not possible to read it, so there will never be bus conflicts with reads with this chip.

Beware: the output is quite weak and is only able to source current; it can't sink current.

[yxkalle]

Thank you very much! Maybe I can use one of the NAND-gates (74HC02) to form a NOT-gate and use a feedback resistor to use it as a crude amplifier to save a chip? Nintendo used that trick to amplify the sound output of the 2A03. Probably I should just use an op-amp, but I like "elegant" solutions.

[l_oliveira]

Thank you very much! Maybe I can use one of the NAND-gates (74HC02) to form a NOT-gate and use a feedback resistor to use it as a crude amplifier to save a chip? Nintendo used that trick to amplify the sound output of the 2A03. Probably I should just use an op-amp, but I like "elegant" solutions.

That's how the ORIGINAL game works so I don't see why that wouldn't work.

Edit: I think it has to be HCU type though ...

[yxkalle]

I think the 74HC will work just fine. Sure, HCU's are more linear and work from rail to rail, but for beeps and bloops it should work just fine(?) I will test it.

EDIT:
The famicom uses a 74HC368 for its sound.

[l_oliveira]

I think the 74HC will work just fine. Sure, HCU's are more linear and work from rail to rail, but for beeps and bloops it should work just fine(?) I will test it.

HC won't work because it "won't oscillate"... I mean it won't amplify anything. I tried some and it didn't go well. Nintendo used HCU for a reason and I understood when I tried to mimic their circuit. Well try it and let us know how it goes !

[yxkalle]

http://www.fairchildsemi.com/an/AN/AN-88.pdf

Not very linear indeed, but it should work. I don't have the parts yet.

[aodinets]

Yes, I did exactly that and it works. Interestingly, R/W doesn't really work on this chip and it is not possible to read it, so there will never be bus conflicts with reads with this chip.

Beware: the output is quite weak and is only able to source current; it can't sink current.

Hi, all!
What do you think about this schematic with YMZ284 sound?

[aodinets]

Anybody???

[l_oliveira]

Lacks an amplifier. Even if the logic is fine the sound will be too low on volume.

[aodinets]

Lacks an amplifier. Even if the logic is fine the sound will be too low on volume.

Amplifier is not a problem. Logic is important...

[l_oliveira]

Lacks an amplifier. Even if the logic is fine the sound will be too low on volume.

Amplifier is not a problem. Logic is important...

Did you try building that ? I never tried that particular chip. I did try the GI AY-3-8910 and YM2149. Nothing else. The logic would be different depending on how the enable works for your chip.

[yxkalle]

I was under the impression a clock divider wasn't needed? If you look at the data sheet you can see a clock divider in the block diagram. Can someone spread some light on this?

[l_oliveira]

I was under the impression a clock divider wasn't needed? If you look at the data sheet you can see a clock divider in the block diagram. Can someone spread some light on this?

I did not need any when I used the YM2149. AY-3-8910 did require it.

[infiniteneslives]

Neither the 8910 nor the 2149 is self sufficient, but they're each lacking different things.

AY-3-8910: You must add a clock divider since it doesn't have one built in. However it's output doesn't require an amplifier.
YM2149: Has built in clock divider, but has a weak output so you have to add an amplifier.

Both require the same address decoder.