Datasheet

Section 13 Timer Z
Rev.5.00 Nov. 02, 2005 Page 245 of 500
REJ09B0027-0500
4. Contention between TCNT Write and Overflow/Underflow: If overflow/underflow occurs in
the T
2
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.
T 1 T 2
TCNT H'FFFF M
OVF
TCNT address
WTCNT
(internal write signal)
TCNT input clock
Overflow signal
TCNT write data
TCNT write cycle
φ
Figure 13.55 Contention between TCNT Write and Overflow