Datasheet

Section 11 16-Bit Timer Pulse Unit (TPU)
Rev. 6.00 Mar. 18, 2010 Page 398 of 982
REJ09B0054-0600
11.4 Operation
11.4.1 Basic Functions
Each channel has a TCNT and TGR register. TCNT performs up-counting, and is also capable of
free-running operation, periodic counting, and external event counting.
Each TGR can be used as an input capture register or output compare register.
Counter Operation: When one of bits CST2 to CST0 (H8S/2227 Group) or bits CST5 to CST0
(groups other than H8S/2227) in TSTR is set to 1, the TCNT counter for the corresponding
channel starts counting. TCNT can operate as a free-running counter, periodic counter, and so on.
1. Example of count operation setting procedure
Figure 11.3 shows an example of the count operation setting procedure.
Select counter clock
Operation selection
Select counter clearing source
Periodic counter
Set period
Start count
<Periodic counter>
[1]
[2]
[4]
[3]
[5]
Free-running counter
Start count
<Free-running counter>
[5]
[1]
[2]
[3]
[4]
[5]
Select output compare register
Select the counter
clock with bits TPSC2
to TPSC0 in TCR. At
the same time, select
the input clock edge
with bits CKEG1 and
CKEG0 in TCR.
For periodic counter
operation, select the
TGR to be used as the
TCNT clearing source
with bits CCLR2 to
CCLR0 in TCR.
Designate the TGR
selected in [2] as an
output compare
register by means of
TIOR.
Set the periodic
counter cycle in the
TGR selected in [2].
Set the CST bit in
TSTR to 1 to start the
counter operation.
Figure 11.3 Example of Counter Operation Setting Procedure