totty@flute.cs.uiuc.edu (Brian Totty) (09/18/90)
I have a MIDI interface that we have plugged into a Mac II serial port which we can access under the Mac OS which we want to access under A/UX. To generate MIDI speeds, it is necessary to set some serial communications controller registers to tell it to expect an external clock and use different dividers. We have Mac OS code to do this. I want to be able to configure the SCC chip under A/UX, and then preferably be able to use the standard serial driver, so I don't have to rewrite an entire serial driver from scratch just to use a non-standard baud rate. Please, if anyone has insight or suggestions as the best way to approach this let me know. Will A/UX support this in the future? Please send ideas!!!! --- Bri / Brian Totty o o /__ __ o 1304 W. Springfield Avenue o / / / / Urbana, IL 61801 \_/ "We have corn in /__/ / / totty@cs.uiuc.edu Massachusetts too!"
einhorn@triton.unm.edu (E Drew Einhorn ADV.SCI.Inc) (09/19/90)
In article <1990Sep18.015919.13846@julius.cs.uiuc.edu> totty@flute.cs.uiuc.edu (Brian Totty) writes: > > I have a MIDI interface that we have plugged into a Mac II serial > port which we can access under the Mac OS which we want to access > under A/UX. To generate MIDI speeds, it is necessary to set some > serial communications controller registers to tell it to expect > an external clock and use different dividers. We have Mac OS code > to do this. > Please let us posted on your progress. Before investing too much effort in your MIDI A/UX I would suggest experimenting with a very simple protocol, a single message type and an echo. Measure the average delay and possibly even more important the standard deviation of the delay. After all A/UX does not claim to be a real time unix. Some people believe that general purpose computer with a single user OS needing to update the screen and keep track of the mouse and keyboard introduces unacceptable timing irregularities and recommend dedicated sequencer hardware. (An extreme position). But A/UX based MIDI software is a BIG step in the opposite direction. -- einhorn@triton.unm.edu