[sdiy] SH-101 CPU

[Tom Wiltshire]

The original chip was 40-pin too, so you'd probably need something of  
that size. I'm using a 16F74 for my current MIDI experiments, which  
is a basic 8-bit, 40pin chip. There's a larger version with more  
memory too, the 16F77.
Alternatively, Seb Francis used the 16F877 in his 4xD delay, which is  
another, larger, 40-pin 8-bit chip.

One useful feature you could add would be a MIDI input. Most of these  
modern microchip PICs have a USART on the chip which is ideal for  
MIDI. It's also worth pointing out that the CPU in the SH101  
generates the LFO's random waveform by sending random values to a D/A  
convertor. Given that the hardware is open-ended in this respect, you  
could offer alternative LFO waveforms (staircase perhaps) by  
reprogramming the processor. You have similar options with other  
aspects of the SH101 which are controlled by the uP, such as the  
arpeggiator (new modes or patterns?) and the sequencer (longer  
sequence?).

It's an interesting idea. A replacement uP for the SH101 would be  
fairly simple, and might offer some considerable extras.

T.




On 25 Mar 2009, at 06:21, Kyle Stephens wrote:

>
> As reference for a far-off someday project, of the cloning variety,  
> what would be a modern replacement for the CPU in the SH-101?
>
> I figure I could work backwards from there, once I have at least  
> that down. Best I can narrow things down to is knowing that given  
> the TMP80C49 was 8-bits, a replacement presumably would match that...?
>
>
> _Kyle
>
>
>
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