256 HITACHI
10.4.3
Synchronizing Mode
In the synchronizing mode, two or more timer counters can be rewritten simultaneously
(synchronized preset). Multiple timer counters can also be cleared simultaneously using TCR
settings (synchronized clear). The synchronizing mode can increase the general registers for a
single time base. All five channels can be set for synchronous operation.
Procedure for Selecting the Synchronizing Mode (figure 10.26):
1. Set 1 in the SYNC bit of the timer synchro register (TSNC) to use the channels in the
synchronizing mode.
2. When a value is written in the TCNT in any of the synchronized channels, the same value is
simultaneously written in the TCNT in the other channels.
3. Set the counter to clear with compare match/input capture using bits CCLR1 and CCLR0 in the
TCR.
4. Set the counter clear source to synchronized clear using the CCLR1 and CCLR0 bits.
5. Set the STR bits in the TSTR to 1 to start counting in the TCNT.
Select counter
clear source
Channel that
generated clear
source
No
Yes
Select synchronizing
mode
Set synchronizing mode
Synchronized preset
Set TCNT
Start counting
Select counter
clear source
Start counting
Counter clear
Synchronized clear
Synchronizing preset
Synchronized clear
(1)
(2)
(3)
(5)
(4)
(5)
Figure 10.26 Procedure for Selecting the Synchronizing Mode