Hitachi H8/3664 Hardware Manual page 226

Table of Contents

When compare match is selected as the TCNT clear source, TCNT operates as a periodic counter.

Select the output compare function for GRA, set bit CCLR in TCRW to 1, and set the count period

in GRA. When the count matches GRA, the IMFA flag in TSRW is set to 1 and TCNT is cleared

to H'0000. If the IMIEA bit in TSRW is set to 1 at this time, an interrupt request is sent to the

CPU. After the compare match, TCNT continues counting from H'0000. Figure 12.6 illustrates

periodic counting.

Figure 12.5 Free-Running Counter Operation

Figure 12.6 Periodic Counter Operation

Flag cleared

Flag cleared