[LAD] [Fwd: Re: No nagging, a serious question]

[Ralf Mardorf]

On Sun, 2010-07-04 at 19:08 -0400, Gene Heskett wrote:
> On Sunday 04 July 2010, Gordon JC Pearce wrote:
> >On Sun, 2010-07-04 at 22:16 +0100, Dan Mills wrote:
> >> You could probably hack a multi serial port card to do multiple midi
> >> ports (Change the rock to give a suitable divider for 31250 baud
> >> (4MHz?), add current loop interfaces)...
> >
> >Been there, done that - when I was a penniless dole-scrounging scruffy
> >university drop-out living on a farm in the middle of nowhere, I decided
> >I needed a MIDI sequencer.  So, I modified an old serial card with a
> >4MHz crystal which divides to 31250 baud, and wrote a simple
> >tracker-style sequencer in a mixture of C and assembler on DOS.  It
> >worked, kind of.  If you wanted to do anything really wild like change
> >the tempo you needed to recompile.
> >
> >Gordon MM0YEQ
> >
> As for the serial card with a different crystal, BTDT, on a TRS-80 Color 
> Computer 3.  Not only that, but the software, Ultimuse-III, written by Mike 
> Knudsen could handle the serial card and the bitbanger at the same time, so 
> I actually had 2 ports and drove two different midi keyboards each with 
> their own midi voice assignments.  This on a machine with 60 ticks/second 
> IRQ's for a clock.  And neither port had any extra added buffers, it Just 
> Worked(TM).

60 ticks/second IRQ's for clock is for the C64 too, the UART was
connected to the bus, but a serial port.