FC5Ch Latch 74LS273 (IC8) for COM8116 (IC9)
Bit7-4 Channel A RX/TX Clock Bit3-0 Channel B RX/TX Clock FC7Ch [[Z80-DART/Z80-SIO chip|Z80 SIO]] Channel A Data FC7Dh [[Z80-DART/Z80-SIO chip|Z80 SIO]] Channel A Control/Status FC7Eh [[Z80-DART/Z80-SIO chip|Z80 SIO]] Channel B Data FC7Fh [[Z80-DART/Z80-SIO chip|Z80 SIO]] Channel B Control/Status
For details on the Z80 SIO, see [[Z80-DART/Z80-SIO chip]].
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 HzThe baudrates can be further divided by 1,16,32,64 inside of the Z80 SIO. [[httpMedia://www.cpcwiki.eu/imgs/b/b8/Rs232fr.zip]] All scans- Scanned DIY article (8 pages).