ee163ahq@sdccs7.UUCP (Doug Salot) (06/10/84)
-- My roommate is in the process of acquiring a Yamaha DX-7 Synth. He is interested in interfacing to a microcomputer via the DX-7's MIDI ports so that the micro may act as a sequencer and other fun things. I suggested that he look into the Sanyo MBC-550 for the micro end (primarily because I have one I'd like to sell), and we're interested in anybody's thoughts on the feasiblity of this project. My main concern revolves around the fact that the MIDI goes at 31.25 Kbaud, asynch at TTL levels. The Sanyo has a serial port which uses Intel's 8251. The 8251 gets its timing signals from one of the programmable timers on the Sanyo. My plan was to bypass the voltage level shifters on the RS-232 card and program the 8251 to go at a sufficiently swift rate. Theoretically, I can program the 8251 to go at 111.9 / N Kbaud for N = 1..some_large_number. This leaves me with 27.9 Kbaud and 37.3 Kbaud as the closest I can come to the 31.25 Kbaud that I need. My question is two-fold: can the 8251 actually go at these higher baud rates (19.2 Kbaud is the highest I've seen for RS-232), and is a 10% error in baud rate tollerable for the MIDI? Please respond by mail to sdccs7!ee163ahq or sdcarl!rb -- ThankSalot Doug Salot ..sdcsvax!sdccs7!ee163ahq