== I/O Ports ==
Contains a HD146818P (RTC) and , a TMP[[Z80 PIO|Z84C20]]P ([[Z80 PIO]]) , three logic chips, and a 3.6V battery.
* Reportedly: DK-Tronics RTC module used a the [[Z80 PIO]] chip to address the RTC itself
as Port A of the PIO, with a 9-pin user i/o port as Port B.