R. MEIER <rmeier@Su-Star.ARPA> (01/28/85)
Jim, I have the following arrangement of cards and have not had a problem. Slot 0:128K ram Slot 1:Super-Serial Card (modem) Slot 2:Apple Serial Card (printer) Slot 3:80-col card Slot 4:Z80 card Slot 5:vacant Slot 6:disk Slot 7:vacant Within the configuration block of CP/M, I have routines to make the 128K ram look like a disk, the Slot 2 Apple Serial Card look like a printer with DTR flow control, and the Super-Serial Card look like another console. The Apple Serial Card has no flow control on board, but since the printer doesn't transmit, I switched the DTR and REC lines on the RS-232 connector. The Apple Serial Card is nothing but a ROM, line driver, and line sensor that I can read/write directly. The ROM contains software for RS-232 timing, so I use it to output a byte at a time, but I only send it a byte after reading that the DTR line is high. The Super-Serial Card has flow control on board and so is called in the normal fashion of a port/status register pair. If the above superficial view is helpful, then fine, otherwise, write me at rmeier@star.arpa. Bob (rmeier@star.arpa) ------