[sdiy] Parallel 8 Bit DACS?

rsdio at sounds.wa.com rsdio at sounds.wa.com
Tue Dec 10 18:30:49 CET 2013


On Dec 10, 2013, at 05:25, Jack Jackson wrote:
> Here's an example of what I meant with daisy chaining on the Solton  
> Programmer EPROMs
>
> http://soundsofthedot.com/images/daisy.png

That's called a bus. On the left is an address bus, 14 bits wide (not  
quite 16). On the right is the data bus, 8 bits wide. This circuit  
shows all ROM chips on a shared bus, meaning that they have to be  
multiplexed and read just one at a time. The 4051 chips at IC-70 and  
IC-71, along with the individual S/H stages, serve to demultiplex the  
individual sounds into separate signals.

Daisy chaining is when the output of one device feeds the input of  
the next device, and so on. This Solton circuit is not daisy chained  
because the same address bus feeds the address input pins on all ROM  
chips, and the ROM outputs all connect to the same data bus. You'd  
have to see ROM data outputs feeding ROM address inputs for daisy  
chaining. The latter is something you might do to translate encoded  
ROMs on the fly. I can't think of any valid use for a ROM daisy chain  
deeper than one pair.

Brian Willoughby
Sound Consulting




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