Panasonic MN101C00 - Manual (Page 84)

Figure 4-3-1 Binary Counter 4 (TM4BC) Count Timing
Chapter 4 Timer Functions
70
Clock
TM4EN
Binary
counter 4
Write to registers
TM4OCH, TM4OCL
05 04 06 07 08 09 00
If the TM4EN flag of the TM4MD register is changed simultaneously
with other bits, the switching operation may cause binary counter 4
to be incremented.
If the value of the TM4OCH, TM4OCL register is overwritten while
timer 4 has stopped counting, binary counter 4 will be reset to
X'0000'.
16-bit Timer Operation (timer 4)