Path: utzoo!utgpu!watmath!clyde!att!lzaz!hcj
From: hcj@lzaz.ATT.COM (HC Johnson)
Newsgroups: comp.os.minix
Subject: MINIX/ST  MDI and KBD Blues
Keywords: ST MIDI MDI KBD
Message-ID: <284@lzaz.ATT.COM>
Date: 29 Nov 88 17:18:40 GMT
Organization: AT&T ISL Lincroft NJ USA
Lines: 33





I have been working on both  MIDI and RS232 drivers for minix.
I have encountered the following.
1. There is something I can do in the keyboard that locks up the system.
   This seems related to fumbling around alt,ctrl,and shift.
2. Most attempts to read in MIDI interrupts lock up the system.
3. I think 1. and 2. are related.
4. Minix handles the MFP differently from TOS. TOS uses manual interrupt
   acknowledgement ( the S bit). Minix goes for automatic acknowledgment.
5. The KBD handler seems to work because it tries to poll out all the 
   characters being sent to it after the first interrupt.
   while(KBD->ac_cs & IRQ) {
       code = KBD->ac_da;
      ... lots of processing
  }
6. The same for MIDI fails unless I add a delay in the loop.

How about it.  Anyone else try this stuff.  Am I the only one going
crazy trying this.

PS. work in progress in Lincroft:
  MIDI
  RS232
  Ptrace(...)
  ADB port.


Howard C. Johnson
ATT Bell Labs
...lzaz!hcj