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.

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  Schematic

Media:Rs232fr.zip - Scanned DIY article (8 pages).