Datasheet

Section 11 16-Bit Timer Pulse Unit (TPU)
R01UH0309EJ0500 Rev. 5.00 Page 743 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
(b) Free-running count operation and periodic count operation
Immediately after a reset, the TPU's TCNT counters 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 (changes 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, the TPU requests an interrupt. After overflow, TCNT starts counting up again
from H'0000.
Figure 11.4 illustrates free-running counter operation.
TCNT value
H'FFFF
H'0000
CST bit
TCFV
Time
Figure 11.4 Free-Running Counter Operation