Datasheet

Section 14 16-Bit Timer Pulse Unit (TPU)
Rev. 2.00 Jul. 04, 2007 Page 290 of 692
REJ09B0309-0200
14.5 Operation
14.5.1 Basic Functions
Each channel has TCNT and TGR. TCNT performs up-counting, and is also capable of free-
running operation, periodic counting, and external event counting.
TGR can be used as an input capture register or output compare register.
(1) Counter Operation
When one of bits CST1 and CST2 is set to 1 in TSTR, TCNT for the corresponding channel
begins counting. TCNT can operate as a free-running counter, periodic counter, for example.
(a) Example of Count Operation Setting Procedure
Figure 14.5 shows an example of the count operation setting procedure.
Operation selection
Select counter clock
Periodic counter
Select counter clearing source
Select output compare register
Set period
Free-running counter
Start count operation
<Free-running counter><Periodic counter>
Start count operation
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
TGR to be used as
the TCNT clearing
source with bits
CCLR1 and CCLR0 in
TCR.
Designate TGR
selected in [2] as an
output compare
register by means of
TIOR.
Set the periodic
counter cycle in
TGR selected in [2].
Set the CST bit in
TSTR to 1 to start
the counter
operation.
[1]
[1]
[2]
[2]
[3][3]
[4]
[4]
[5]
[5]
Figure 14.5 Example of Counter Operation Setting Procedure