Section 13 Timer Z
4. Contention between TCNT Write and Overflow/Underflow: If overflow/underflow occurs in
the T2 state of a TCNT write cycle, TCNT write has priority without an increment operation.
At this time, the OVF flag is set to 1. Figure 13.55 shows the timing in this case.
TCNT write cycle
T
1
T2
φ
TCNT address
WTCNT
(internal write signal)
TCNT input clock
Overflow signal
TCNT
H'FFFF
M
TCNT write data
OVF
Figure 13.55 Contention between TCNT Write and Overflow
Rev. 3.00 Sep. 10, 2007 Page 270 of 528
REJ09B0216-0300