NEC 78K0/KD1 Series User Manual page 138

(5) Port mode register 0 (PM0)
This register sets port 0 input/output in 1-bit units.
When using the P01/TO00/TI010 pin for timer output, set PM01 and the output latch of P01 to 0.
PM0 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets PM0 to FFH.
138
CHAPTER 6 16-BIT TIMER/EVENT COUNTER 00
Figure 6-6. Format of Port Mode Register 0 (PM0)
Address: FF20H After reset: FFH
Symbol 7 6 5
PM0 1 1 1
PM0n P0n pin I/O mode selection (n = 0 to 3)
0 Output mode (output buffer on)
1 Input mode (output buffer off)
Preliminary User's Manual U16315EJ1V0UD
R/W
4 3 2 1 0
1 PM03 PM02 PM01 PM00