Rs-232 vs MIDI vs SCSI?

[brad sanders]

First, the MIDI data rate was NOT chosen simply "because that's as
fast as an 8051 could talk." A 12MHz 8051 can "talk" at 1Mbps.

The MIDI data rate was chosen for convenience. If you'll look at the
sample rate of MIDI devices you'll notice a correlation between sample
rate and MIDI data rate (1 digital  "sample" time = 1 MIDI bit time).
It's simple as that.

No matter WHAT I/O protocol you use, there is FAR more to "porting" an
invention to the MAC than just using the right electrical interface.
You could use RS232, SCSI, PCI, or even an enhanced parallel port - it
would STILL require the proper software to use with a MAC.

SCSI will allow oodles of bandwidth - and limit you to using a fat,
short cable. You might as well use an EPP port and save PC owners from
having to buy a SCSI card.

However, ANY parallel port protocol is just plain stupid in this
application (sorry for being so blunt - but it is). If you want a PCI
card, that's fine - but you can get plenty of bandwidth via far more
economic channels. PCI requires a pretty sophisticated bus interface
controller chip - unlike ISA, which requires little more than a few
digital buffers.

RS422 supports *in theory* up to 10Mbps or so. Based on more than a
decade of experience, I can tell you this only works in THEORY. You
might get 10Mbps over a short cable, but you're NOT going to do this
with any sort of "network." Plan for 1Mbps TOPS.

NO MATTER the medium (RS422, RS232, MIDI, USB) it is NOT a "trivial"
task to "retrofit" equipment. A serial port is a serial port - NOT.
Some use MSB first, some use LSB first, and EACH of the above has it's
own protocol.

If you want to make a new design "portable," use a USB port. You can
buy USB microcontrollers now for like a buck in high quantities -
figure five bucks for onesy-twoseys. This should certainly be able to
control an "analog" synth.