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Section 11 Multi-Function Timer Pulse Unit 2
Page 508 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
(b) Free-Running Count Operation and Periodic Count Operation:
Immediately after a reset, the TCNT counters of this module are all designated as free-running
counters. When the relevant bit in TSTR is set to 1 the corresponding TCNT counter starts up-
count operation as a free-running counter. When TCNT overflows (from H'FFFF to H'0000), the
TCFV bit in TSR is set to 1. If the value of the corresponding TCIEV bit in TIER is 1 at this point,
this module requests an interrupt. After overflow, TCNT starts counting up again from H'0000.
Figure 11.5 illustrates free-running counter operation.
TCNT value
H'FFFF
H'0000
CST bit
TCFV
Time
Figure 11.5 Free-Running Counter Operation
When compare match is selected as the TCNT clearing source, the TCNT counter for the relevant
channel performs periodic count operation. The TGR register for setting the period is designated
as an output compare register, and counter clearing by compare match is selected by means of bits
CCLR0 to CCLR2 in TCR. After the settings have been made, TCNT starts up-count operation as
a periodic counter when the corresponding bit in TSTR is set to 1. When the count value matches
the value in TGR, the TGF bit in TSR is set to 1 and TCNT is cleared to H'0000.
If the value of the corresponding TGIE bit in TIER is 1 at this point, this module requests an
interrupt. After a compare match, TCNT starts counting up again from H'0000.