wolpert@hpislx.HP.COM (David Wolpert) (07/27/88)
I finally found time to build (and test) the level converters necessary to get my Model 100 to speak MIDI. Next question: how do I get it to _hear_ MIDI? I figured out how to change the baud rate, and now I can play tunes on my piano. But when I try to send stuff from the piano keyboard to the computer, all I get is zeroes or 255's. I think when I try to do an INPUT$, the baud rate changes back to 9600 or something; and if I try to read the UART port directly, the byte has already been taken away by the interrupt processing (RST 6.5, I think). So where does the interrupt routine put the byte it gets from the serial port? Is this info somewhere in the technical reference manual? Do I need to replace the interrupt routine with one of my own? Does somebody have commented listings of the firmware? Is there a book I can buy that tells me all this? Or, better yet, has anybody done a cheap Model 100 MIDI library for Ensoniq/Yamaha/Roland/etc.? By the way, the hardware to do this was pretty simple: an optoisolator, a couple of diodes, some resistors, a MIDI cable and a DB25 connector. The "electronics" is wired on a small PC prototype board that fits inside the connector shell, so it even looks nice. The output current is only about one milliamp (MIDI spec is five, I think), but it works with every MIDI synthesizer I've tried (yeah, I know, probably not at 40 deg/95 pct; if I were doing this as an HP product, it would have to have batteries :-). Any help is appreciated; maybe I can return the favor. Thanks in advance. -- _ _ / \/ \ David Wolpert (303) 679-3533 /_ __ HEWLETT \ / Measurement Systems Operation / / /_/ PACKARD \ / Box 301 - Loveland, CO 80539 / \/ wolpert%hpisla@hplabs.HP.COM ====================================================================== "Be joyful always; pray continually; give thanks in all circumstances"
oster@dewey.soe.berkeley.edu (David Phillip Oster) (08/15/88)
See "Inside the TRS-80 Model 100" by Carl Oppendahl, $19.95 from Weber Systems, Inc. 8437 Maysfield Road, Chesterland, Ohio, 44026 for details on the serial drivers in the Model 100. Sounds like an interesting project. I can see downloading a patch library and a set of sequences from your main computer so you'll have them ready for a gig. --- David Phillip Oster --When you asked me to live in sin with you Arpa: oster@dewey.soe.berkeley.edu --I didn't know you meant sloth. Uucp: {uwvax,decvax,ihnp4}!ucbvax!oster%dewey.soe.berkeley.edu