[sdiy] New to list - and DSP development

[Rainer Buchty]

>The CPUs in typical synths is an even multiple of 1 MHz, so that way I
>suspect they would count on saving an oscillator. I'm not sure I would
>make the choice differenly.

Actually, that might well be the reason.

In PC/XT the UART frequency (1.8432MHz) was derived from 14.7456MHz
which IIRC is 4 times the NTSC color subcarrier.

As you say, MIDI timing is based on an even multiple of 1MHz. If you
want to convert any vanilla serial card to MIDI, either apply
16MHz to the 14.7456MHz input or 2MHz to the 1.8432MHz input. Then use
OS settings for 28k8 to get 31k25.

>Most other units would also be able to handle this. It's a mystery why
>this was not included into the standard, or maybe it's not as much of a
>mystery :-P

Interestingly, a number of internal buses of older machines run off
"double MIDI".

Rainer