Table of Contents
Advertisement
12.5
Usage Notes
12.5.1
Register Writes
When performing a register write, timer count operation must be stopped by clearing the start bit
(STR0–STR2) for the relevant channel in the timer start register (TSTR).
Note that the timer start register (TSTR) can be written to, and the underflow flag (UNF) and input
capture flag (ICPF) of the timer control registers (TRCR0 to TCR4) can be cleared while the count
is in progress. When the flags (UNF and ICPF) are cleared while the count is in progress, make
sure not to change the values of bits other than those being cleared.
12.5.2
TCNT Register Reads
When performing a TCNT register read, processing for synchronization with the timer count
operation is performed. If a timer count operation and register read processing are performed
simultaneously, the TCNT counter value prior to the count-down operation is read by means of the
synchronization processing.
12.5.3
Resetting the RTC Frequency Divider
When the on-chip RTC output clock is selected as the count clock, the RTC frequency divider
should be reset.
12.5.4
External Clock Frequency
Ensure that the external clock frequency for any channel does not exceed Pφ/4.
Rev. 4.0, 04/00, page 256 of 850
Advertisement
Table of Contents
