FBE3h Dk'tronics Real Time Clock - [[Z80 PIO]] Port B Control
FBE8h Dk'tronics Real Time Clock - Control port for RTC chip (4bit latch) '''(details unknown)'''
Do not use Port A as this will affect the RTC operation.
PIO Port A seems to be the plain RTC Data Bus, there should be also RTC Read and Write signals, which are maybe found in the '''(details unknown)''' port?