Hitachi H8S/2646 Hardware Manual page 436

Hitachi 16-bit single-chip microcomputer h8s/2646 series

Table of Contents

Example of Normal Pulse Output (Example of Five-Phase Pulse Output): Figure 11-5 shows

an example in which pulse output is used for cyclic five-phase pulse output.

Figure 11-5 Normal Pulse Output Example (Five-Phase Pulse Output)

[1] Set up the TPU channel to be used as the output trigger channel so that TGRA is an output

compare register and the counter will be cleared by compare match A. Set the trigger period in

TGRA and set the TGIEA bit in TIER to 1 to enable the compare match A (TGIA) interrupt.

[2] Write H'F8 in P1DDR and NDERH, and set the G3CMS1, G3CMS0, G2CMS1, and G2CMS0

bits in PCR to select compare match in the TPU channel set up in the previous step to be the

output trigger. Write output data H'80 in NDRH.

[3] The timer counter in the TPU channel starts. When compare match A occurs, the NDRH

contents are transferred to PODRH and output. The TGIA interrupt handling routine writes the

next output data (H'C0) in NDRH.

[4] Five-phase overlapping pulse output (one or two phases active at a time) can be obtained

subsequently by writing H'40, H'60, H'20, H'30. H'10, H'18, H'08, H'88... at successive TGIA

interrupts. If the DTC is set for activation by this interrupt, pulse output can be obtained

without imposing a load on the CPU.

Compare match