FBE0h  Dk'tronics Real Time Clock - [[Z80 PIO]] Port A Data ([[PC compatible RTC chip|HD146818P]] RTC Data bus)
  FBE1h  Dk'tronics Real Time Clock - [[Z80 PIO]] Port B Data, used for external control (General Purpose 8bit I/O Port)
  FBE2h  Dk'tronics Real Time Clock - [[Z80 PIO]] Port A Control (do not use as this will affect the RTC operation)
  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?