Synchronous Operation - Hitachi H8S/2338 Series Hardware Manual

7.4.3

Synchronous 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 7-14 shows an example of the
synchronous operation setting procedure.
Synchronous operation
selection
Set synchronous
operation
Synchronous presetting
Set TCNT
<Synchronous presetting>
[1] Set to 1 the SYNC bits in TSYR corresponding to the channels to be designated for synchronous operation.
[2] 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.
[3] Use bits CCLR2 to CCLR0 in TCR to specify TCNT clearing by input capture/output compare, etc.
[4] Use bits CCLR2 to CCLR0 in TCR to designate synchronous clearing for the counter clearing source.
[5] Set to 1 the CST bits in TSTR for the relevant channels, to start the count operation.
Figure 7-14 Example of Synchronous Operation Setting Procedure
280
[1]
Synchronous clearing
[2]
Clearing
source generation
channel?
Yes
Select counter
clearing source
Start count
<Counter clearing>
No
Set synchronous
[3]
counter clearing
[5] Start count
<Synchronous clearing>
[4]
[5]