Datasheet

Section 14 Timer Z
Rev. 3.00 Mar. 15, 2006 Page 237 of 526
REJ09B0060-0300
14.4 Operation
14.4.1 Counter Operation
When one of bits STR0 and STR1 in TSTR is set to 1, the TCNT counter for the corresponding
channel begins counting. TCNT can operate as a free-running counter, periodic counter, for
example. Figure 14.7 shows an example of the counter operation setting procedure.
[1] Select the counter clock with bits
TPSC2 to TPSC0 in TCR.
When an external clock is selected,
select the external clock edge
with bits CKEG1 and CKEG0 in TCR.
[2] For periodic counter operation, select
the TCNT clearing source with bits
CCLR2 to CCLR0 in TCR.
[3] Designate the general register
selected in [2]
as an output compare register by
means of TIOR.
[4] Set the periodic counter cycle in the
general register selected in [2].
[5] Set the STR bit in TSTR to 1 to start
the counter operation.
Operation selection
Periodic counter
Free-running counter
[1]
Select counter clock
[2]
Select counter clearing source
[3]
Select output compare register
[5]
Start count operation
[4]
Set period
Figure 14.7 Example of Counter Operation Setting Procedure