NEC PD78214 - Manual (Page 217)

188
µ
PD78214 Sub-Series
Even if the value of the CR20 compare register coincides with the value of 8-bit timer 2 (TM2) more than once during
one period of PPG output, the output level on the timer output (TO2) is not inverted.
Fig. 7-93 Example of Rewriting Compare Register CR20
TO2
T1 T2
T1 T1
T2 T2
CR21
TM2
count value
CR20
Rewriting
CR20
TO2 does not change though CR20 coincides with TM2
CR21 CR21
Remark ALV2 = 1
Cautions 1. If a value less than the value of 8-bit timer 2 (TM2) is written into the CR20 compare register before the value of CR20 coincides
with the value of TM2, a PPG signal with a 100% duty factor is output in that period. Rewrite CR20, if required, by using an
interrupt generated by a coincidence between TM2 and CR20.
Fig. 7-94 Example of PPG Output Signal with a 100% Duty Factor
TO2
CR20
0H
n1 n2
n2
n2 n2
n3
n1
CR20
TM2
count value
When a value, n2 less than TM2 value, n3 is written to CR20
here, the duty factor is 100% during this period.
n1
CR20 CR20 CR20
Remark ALV2 = 0