Freescale Semiconductor MC68HC08KH12 - Manual (Page 240)

Advance Information MC68HC(7)08KH12 — Rev. 1.1
240 Freescale Semiconductor
the break flag control register (BFCR) enables software to clear status
bits during the break state.
To allow software to clear the keyboard interrupt latch during a break
interrupt, write a logic 1 to the BCFE bit. If a latch is cleared during the
break state, it remains cleared when the MCU exits the break state.
To protect the latch during the break state, write a logic 0 to the BCFE
bit. With BCFE at logic 0 (its default state), writing to the keyboard
acknowledge bit (ACKx) in the keyboard status and control register
during the break state has no effect.