Hitachi H8S/2645, Hardware Manual

Page: 377 / 1153

345
10.4.3Synchronous Operation
In synchronous operation, the values in a number of TCNT counters can be rewritten
simultaneously (synchronous presetting). Also, a number of TCNT counters can be cleared
simultaneously by making the appropriate setting in TCR (synchronous clearing).
Synchronous operation enables TGR to be incremented with respect to a single time base.
Channels 0 to 5 can all be designated for synchronous operation.
Example of Synchronous Operation Setting Procedure: Figure 10-14 shows an example of the
synchronous operation setting procedure.
Set synchronous
operation
Synchronous operation
selection
Set TCNT
Synchronous presetting
<Synchronous presetting>
[1]
[2]
Synchronous clearing
Select counter
clearing source
<Counter clearing>
[3]
Start count [5]
Set synchronous
counter clearing
<Synchronous clearing>
[4]
Start count [5]
Clearing
sourcegeneration
channel?
No
Yes
[1]
[2]
[3]
[4]
[5]
Set to 1 the SYNC bits in TSYR corresponding to the channels to be designated for synchronous
operation.
When the TCNT counter of any of the channels designated for synchronous operation is
written to, the same value is simultaneously written to the other TCNT counters.
Use bits CCLR2 to CCLR0 in TCR to specify TCNT clearing by input capture/output compare,
etc.
Use bits CCLR2 to CCLR0 in TCR to designate synchronous clearing for the counter clearing
source.
Set to 1 the CST bits in TSTR for the relevant channels, to start the count operation.
Figure 10-14 Example of Synchronous Operation Setting Procedure