D1749@applelink.apple.com (Disini SW, Emmanuel Disini,PRT) (09/03/90)
Hi. We seem to be having problems with ADSP over here. Whenever we receive serial data (at speeds of 9600 baud or higher) on a MacPlus running an ADSP session, some SCC hardware overruns occur. It seems that ADSP is turning off interrupts for a pretty long time (at least 3.12 ms), so that the SCC's 3 byte buffer is filled. I can receive serial data with no overruns at 19200 bps even when heavy-duty AFP, ATP, or DDP traffic is going on, so we know it isn't a problem with Mpp. It isn't a floppy drive problem either because I've experienced no serial data losses at 57600 bps while erasing a floppy (on the same Mac that's receiving the serial data). It *definitely* isn't a problem with our code turning off interrupts, or some other INIT/CDEV. Has anyone ever encountered this problem at all? Joel Disini