simple MIDI?

[The Dark force of dance]

Y-ellow John 'n' all.
        
At 09:24 AM 1/17/98 +0000, John E Blacet wrote:
>Has anyone run across a circuit that will send or receive one midi
>command? Something that is non uP? Maybe not a practical idea, but
>thought I'd check!

I'm not quite sure what you have in mind here but. A lot of people like
those 1602/ AY3-10xx whatever UARTs for this kinda thing. Big and dumb 40
pin suckers. You can hard wire them so that they will have no choice to
either send or receive MIDI data as and when It enters the chip. There are
no registers or command sequences. It's all done through pins on the chip.
Your very much basic UART.

For example you could set it up so that you have a magnitude comparator
hanging off the 8 bit port. This is set up to detect the MIDI clock signal
which is a single byte. Whenever one comes along it will emit a pulse. By
further dividing that pulse but 24 or 48 you get you basic measure pulse or
whatever.

I've not really looked into this but it should be the same deal in the other
direction. It should just send what ever you present to it's 8 bit output port.

I can't remember the numbers off hand and I hope someone else here will be
able to fill in the blanks but it's important to get the later version of
these chips if you can because otherwise it's hit or miss if the things will
be fast enough to attain MIDI speed. These things are still being made
however from what I gather. These days they are largely unique in the field
of serial conversion but in days gone by, all serial ports were done this
way. Have a look inside a Trash80 expander some time. Scary stuff. And we
use to wonder why they'd mysteriously crash the modem.

Hope that helps.

Be absolutely Icebox.
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