r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 839

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

13.8.4
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 13.5.
Table 13.5 Timer Output Priorities
Output Setting
Toggle output
1 output
0 output
No change
13.8.5
TCNT may increment erroneously when the internal clock is switched over. Table 13.6 shows the
relationship between the timing at which the internal clock is switched (by writing to the CKS1,
CKS0, ICKS1, and ICKS0 bits) and the TCNT operation.
When the TCNT clock is generated from an internal clock, the rising edge or falling edge of the
internal clock pulse is detected. Therefore, when the falling edge is selected, if clock switching
causes a change from high to low level, as shown in case 3 in table 13.6, a TCNT clock pulse is
generated and the TCNT incremented on the assumption that the switchover is a falling edge. This
is the same as when the rising edge is selected.
The erroneous incrementation can also happen when switching between the rising edge and falling
edge of an internal clock or switching between internal and external clocks.
Contention between Compare Matches A and B
Switching of Internal Clocks and TCNT Operation
Rev. 1.00 Sep. 19, 2008 Page 809 of 1342
Section 13 8-Bit Timers (TMR)
Priority
High
Low
REJ09B0467-0100