h8s-2172 Renesas Electronics Corporation., h8s-2172 Datasheet - Page 311

• Manufacturer Part Number: h8s-2172
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family H8s-2100 Series
• Manufacturer: Renesas Electronics Corporation.

9.8.4
If compare match events A and B occur at the same time, the 8-bit timer operates in accordance
with the priorities for the output statuses set for compare match A and compare match B, as shown
in table 9.4.
Table 9.4
9.8.5
TCNT may increment erroneously when the internal clock is switched over. Table 9.5 shows the
relationship between the timing at which the internal clock is switched (by writing to the CKS1
and CKS0 bits) and the TCNT operation.
When the TCNT clock is generated from an internal clock, the falling edge of the internal clock
pulse is detected. If clock switching causes a change from high to low level, as shown in case 3 in
table 9.5, a TCNT clock pulse is generated on the assumption that the switchover is a falling edge.
This increments TCNT.
The erroneous incrementation can also happen when switching between internal and external
clocks.
Output Setting
Toggle output
1 output
0 output
No change
Contention between Compare Matches A and B
Switching of Internal Clocks and TCNT Operation
Timer Output Priorities
Rev. 2.00, 03/04, page 279 of 534
Priority
High
Low