When used as RS232 Baudrate Generator (ie. as in the CPC), all three registers should be set to square-wave non-bcd lsb-then-msb (ie. write values 36h, 76h, and B6h to this port).
== Datasheets ==
* [[Media:8253.pdf]] - 8253 Datasheet (slower clock, write-only control registers)
* [[Media:8254.pdf]] - 8254 Datasheet (faster clock, read/write-able control registers)