Operation; Basic Functions; Figure 9.3 Example Of Counter Operation Setting Procedure - Renesas H8SX/1520 Series Hardware Manual

9.4

Operation

9.4.1

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.
(1)
Counter Operation
When one of bits CST0 to CST5 is set to 1 in TSTR, the TCNT counter for the corresponding
channel starts counting. TCNT can operate as a free-running counter, periodic counter, and so on.
(a)
Example of count operation setting procedure
Figure 9.3 shows an example of the count operation setting procedure.
Select counter clearing source
Select output compare register
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Operation selection
Select counter clock [1]
Periodic counter
[2]
[3]
Set period [4]
Start count [5]
<Periodic counter>

Figure 9.3 Example of Counter Operation Setting Procedure

Section 9 16-Bit Timer Pulse Unit (TPU)
Free-running counter
Start count
<Free-running counter>
Rev. 3.00 Mar. 14, 2006 Page 299 of 804
[1]
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.
[2]
For periodic counter
operation, select the
TGR to be used as
the TCNT clearing
source with bits
CCLR2 to CCLR0 in
TCR.
[3]
Designate the TGR
selected in [2] as an
output compare
register by means of
TIOR.
[4]
Set the periodic
counter cycle in the
TGR selected in [2].
[5]
[5]
Set the CST bit in
TSTR to 1 to start
the counter
operation.
REJ09B0104-0300