Usage Notes; Register Writes; Tcnt Register Reads; Resetting The Rtc Frequency Divider - Hitachi SH7751 Hardware Manual

Table 12.3 TMU Interrupt Sources

Channel Interrupt Source
0 TUNI0
1 TUNI1
2 TUNI2
TICPI2
3 TUNI3
4 TUNI4
12.5

Usage Notes

12.5.1

Register Writes

When performing a TMU register write, timer count operation must be stopped by clearing the
start bit (STR0–STR4) for the relevant channel in the timer start register (TSTR, TSTR2).
Note that the timer start register (TSTR, TSTR2) 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 P
Description
Underflow interrupt 0
Underflow interrupt 1
Underflow interrupt 2
Input capture interrupt 2
Underflow interrupt 3
Underflow interrupt 4
Rev. 3.0, 04/02, page 303 of 1064

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