Hardware manual

Rev. 3.0, 09/98, page 152 of 361

7.4.4 Setting of FRC Overflow Flag (OVF)

The FRC overflow flag (OVF) is set to “1” when the FRC overflows (changes from H'FFFF to

H'0000). Figure 7.15 shows the timing of this operation.

FRC

H'FFFF

OCRA

OCRB

H'0000

FTOA

FTOB

Clear counter

Figure 7.15 Setting of Overflow Flag (OVF)

7.5 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 7.4 lists information about these interrupts.

Table 7.4 Free-Running Timer Interrupts

Interrupt Description Priority

ICIA Requested when ICFA and ICIAE are set High

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 Low