Interrupts; Sample Application - Hitachi H8/329 Series Hardware Manual

6.5 Interrupts

The free-running timer can request seven types of interrupts: input capture A to D (ICIA, ICIB,
ICIC, ICID), output compare A and B (OCIA and OCIB), and overflow (FOVI). Each interrupt is
requested when the corresponding enable and flag bits are set. Independent signals are sent to the
interrupt controller for each type of interrupt. Table 6-4 lists information about these interrupts.
Table 6-4. Free-Running Timer Interrupts
Interrupt Description
ICIA Requested when ICFA and ICIAE are set
ICIB Requested when ICFB and ICIBE are set
ICIC Requested when ICFC and ICICE are set
ICID Requested when ICFD and ICIDE are set
OCIA Requested when OCFA and OCIAE are set
OCIB Requested when OCFB and OCIBE are set
FOVI Requested when OVF and OVIE are set

6.6 Sample Application

In the example below, the free-running timer is used to generate two square-wave outputs with a
50% duty cycle and arbitrary phase relationship. The programming is as follows:
(1) The CCLRA bit in the TCSR is set to "1."
(2) Each time a compare-match interrupt occurs, software inverts the corresponding output level
bit in TOCR (OLVLA or OLVLB).
H'FFFF
OCRA
OCRB
H'0000
FTOA
FTOB
FRC
Figure 6-17. Square-Wave Output (Example)
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