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PostPosted: Thu Sep 26, 2013 4:18 pm 
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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


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PostPosted: Thu Sep 26, 2013 5:57 pm 
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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.


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PostPosted: Thu Sep 26, 2013 6:13 pm 
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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. ;)


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PostPosted: Thu Sep 26, 2013 6:34 pm 
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yxkalle wrote:
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 ...


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PostPosted: Thu Sep 26, 2013 7:05 pm 
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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.


Last edited by yxkalle on Thu Sep 26, 2013 7:18 pm, edited 1 time in total.

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PostPosted: Thu Sep 26, 2013 7:13 pm 
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yxkalle wrote:
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 ! :)


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PostPosted: Thu Sep 26, 2013 9:13 pm 
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http://www.fairchildsemi.com/an/AN/AN-88.pdf

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


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PostPosted: Sun Sep 29, 2013 6:35 am 
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Jarhmander wrote:
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?


Attachments:
YMZ284 SCHEMATICS.png
YMZ284 SCHEMATICS.png [ 69.93 KiB | Viewed 1636 times ]


Last edited by aodinets on Mon Oct 07, 2013 4:21 pm, edited 1 time in total.
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PostPosted: Mon Oct 07, 2013 7:02 am 
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Anybody??? :(


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PostPosted: Mon Oct 07, 2013 7:27 am 
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Lacks an amplifier. Even if the logic is fine the sound will be too low on volume.


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PostPosted: Mon Oct 07, 2013 9:17 am 
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l_oliveira wrote:
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...


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PostPosted: Mon Oct 07, 2013 9:30 am 
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aodinets wrote:
l_oliveira wrote:
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.


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PostPosted: Mon Oct 07, 2013 10:45 am 
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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? :)


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PostPosted: Mon Oct 07, 2013 10:49 am 
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yxkalle wrote:
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.


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PostPosted: Mon Oct 07, 2013 11:16 am 
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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.

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