[net.music] rs232 midi interfaces

Ron Natalie <ron@BRL-TGR.ARPA> (02/11/85)

I've seen adds for midi ports for McIntoshes.  Since McIntoshes only
interface though their balsted serial ports, you might be able to adapt
that interface for your own needs.

-Ron

ron@BRL-TGR.ARPA (Ron Natalie) (02/21/85)

Guess again chucko.  32000 bits/sec <=> 32000 baud (as baud is used
in lay terminology).  You don't really think your 4800 baud terminal
is outputing 4800 characters per second do you?

-Ron

RMS.G.HNIJ%MIT-OZ@MIT-MC.ARPA (John S. Labovitz) (02/22/85)

> From: dave%rocksvax.uucp@BRL-TGR.ARPA
> Date: 20 Feb 85 16:35:00 GMT
>
> Typical asynchronous formats use 10 bauds to transmit 8 bits.  (1 start
> bit, 8 data, 1 stop bit)  Assuming that the thing is async, I believe
> it is, then, 30000/8= 3750 bytes/sec which would be sent at a rate of
> 37500 baud.  Most of the UART chips require a 16x clock to synchronize
> the data to its internal shift register so the chip requires a 600Khz
> clock.  Most old UARTS just make this.  I believe this was the reason
> they picked that rate and the crystal for the oscillator is an off the
> shelf value.
>
> Dave
> 
> arpa: Sewhuk.HENR@Xerox.ARPA
> uucp: {allegra,rochester,amd,sunybcs}!rocksvax!dave

actually, midi uses 31.25 kbps.  it comes out to a 500khz clock rate if
used at X16.

unfortunately, my cp/m box has a crystal the correct frequency to generate
all the `standard' baud rates (300, 1200, etc), but i can't get it to do
anything else.

i wish i'd kept my heath h89 -- it had an 8250, and could do any rate
(up to 56kpbs or so).

	@hnij@
-------

MRees.wbst@XEROX.ARPA (03/01/85)

Watch this space.  The prototype MIDI<-->RS232 box is running.

MRees.wbst@Xerox.arpa