Panasonic F77G User Manual page 197

Timing
P1n output (n=0, 2, 4) : Timer output
P1TCNT set level
Timer output
External interrupt 0
(IRQ0)
PITCNT set value="0"
P1n output
(n=0,2,4)
: "0" (Low) output
Figure 4-10-1 Real Time Output Control Timing
Writing to P1OUT register
Real Time Output Control (Port 1)
Chapter 4 I/O Ports
IV - 47