5 Jul
2010
5 Jul
'10
8:33 a.m.
On Sun, 2010-07-04 at 19:08 -0400, Gene Heskett wrote:
On Sunday 04 July 2010, Gordon JC Pearce wrote:
60 ticks/second IRQ's for clock is for the C64 too, the UART was
connected to the bus, but a serial port.
On Sun, 2010-07-04 at 22:16 +0100, Dan Mills
wrote:
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). 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