179
Compare Match Flag Set Timing: The compare match flags (CMFH or CMFL) are set to 1
when a compare match occurs between TCF and OCRF. A compare match signal is generated in
the final state in which the values match (when TCF changes from the matching count value to the
next value). When TCF and OCRF match, a compare match signal is not generated until the next
counter clock pulse.
Timer F Operation States: Table 9.7 summarizes the timer F operation states.
Table 9.7
Timer F Operation States
Operation Mode
Reset
Active
Sleep
Watch
Sub-
active
Sub-
sleep
Standby
TCF
Reset
Functions
Functions
Halted
Halted
Halted
Halted
OCRF
Reset
Functions
Retained
Retained
Retained
Retained
Retained
TCRF
Reset
Functions
Retained
Retained
Retained
Retained
Retained
TCSRF
Reset
Functions
Retained
Retained
Retained
Retained
Retained
9.3.5
Application Notes
The following conflicts can arise in timer F operation.
16-Bit Timer Mode: The output at pin TMOFH toggles when all 16 bits match and a compare
match signal is generated. If the compare match signal occurs at the same time as new data is
written in TCRF by a MOV instruction, however, the new value written in bit TOLH will be
output at pin TMOFH. The TMOFL output in 16-bit mode is indeterminate, so this output should
not be used. Use the pin as a general input or output port.
If an OCRFL write occurs at the same time as a compare match signal, the compare match signal
is inhibited. If a compare match occurs between the written data and the counter value, however, a
compare match signal will be generated at that point. The compare match signal is output in
synchronization with the TCFL clock, so if this clock is stopped no compare match signal will be
generated, even if a compare match occurs.
Compare match flag CMFH is set when all 16 bits match and a compare match signal is generated;
bit CMFL is set when the setting conditions are met for the lower 8 bits.
The overflow flag (OVFH) is set when TCF overflows; bit OVFL is set if the setting conditions
are met when the lower 8 bits overflow. If a write to TCFL occurs at the same time as an overflow
signal, the overflow signal is not output.