NEC 78K0 User Manual page 176

(2) Operation with CR5n changed
(a) CR5n value is changed from N to M before clock rising edge of FFH
→ Value is transferred to CR5n at overflow immediately after change.
t
Count clock
TM5n N N + 1 N + 2
CR5n N
TCE5n H
INTTM5n
TO5n
<1> CR5n change (N → M)
(b) CR5n value is changed from N to M after clock rising edge of FFH
→ Value is transferred to CR5n at second overflow.
t
Count clock
TM5n N N + 1 N + 2
CR5n N
TCE5n H
INTTM5n
TO5n
Caution When reading from CR5n between <1> and <2> in Figure 7-15, the value read differs from the
actual value (read value: M, actual value of CR5n: N).
176
CHAPTER 7 8-BIT TIMER/EVENT COUNTERS 50 AND 51
Figure 7-15. Timing of Operation with CR5n Changed
FFH 00H 01H 02H
M
<2>
FFH 00H 01H 02H N N + 1 N + 2
N
<1> CR5n change (N → M)
User's Manual U16227EJ2V0UD
M M + 1 M + 2 FFH 00H 01H 02H
FFH 00H 01H 02H
<2>
M M + 1 M + 2
M M + 1 M + 2
M