Z80-SIO dual ports RS232 interface for CPC (French)
Philippe Lebel's Z80-SIO dual ports RS232 interface for CPC.
Scans of article from French magazine including description, schematic and PCB project.
FC5Ch Latch 74LS273 (IC8) for COM8116 (IC9) Bit7-4 Channel A RX/TX Clock Bit3-0 Channel B RX/TX Clock FC7Ch Z80 SIO Channel A Data FC7Dh Z80 SIO Channel A Control/Status FC7Eh Z80 SIO Channel B Data FC7Fh Z80 SIO Channel B Control/Status
For details on the Z80 SIO, see Z80-DART/Z80-SIO chip. The circuit supports both Channel A and B. However, for channel B, only RX/TX signals are implemented (though with some modification, one could add a third MAX232 for also supporting RTS/CTS and DTR/DSR).
The COM8116 chip is driven by a 4.9152 MHz crystal. Selectable clock sources are:
0=800 Hz 4=2400 Hz 8=28800 Hz 12=76800 Hz 1=1200 Hz 5=4800 Hz 9=32000 Hz 13=115200 Hz 2=1760 Hz 6=9600 Hz 10=38400 Hz 14=153600 Hz 3=2152 Hz 7=19200 Hz 11=57600 Hz 15=307200 Hz
The baudrates can be further divided by 1,16,32,64 inside of the Z80 SIO.
Media:Rs232fr.zip - Scanned DIY article (8 pages).