SH7021 datasheet(282/509 Pages) RENESAS

282 / 509 page

266 RENESAS

5. GRA3 is the waveform period register. Set the upper limit of TCNT3–1*. Set the transition

times of the PWM output waveforms in GRB3, GRA4, and GRB4. Set times within the

compare match range of TCNT3 and TCNT4.

≤ X

(X: initial setting of GRB3, GRA4, and GRB4; T: initial setting of TCNT3)

Note:

GRA3 = [cycle count/2] + [count of non-overlaps] – 2cyc=[upper limit of TCNT3] – 1

6. Set the STR3 and STR4 bits in the TSTR to 1 to let TCNT3 and TCNT4 start counting.

(1)

(2)

(3)

(4)

(5)

(6)

Set general registers

Start counting

Complementary PWM mode

Stop counting

Select counter clock

Set TCNT

Complementary PWM mode

Select complementary

PWM mode

Note

To re-engage the complementary PWM mode after it has been aborted, start settings

from step 1.

Figure 10.33 Procedure for Selecting the Complementary PWM Mode

Complementary PWM Mode Operation: Figure 10.34 shows an example of operation in the

complementary PWM mode. TCNT3 and TCNT4 operate as up/downcounters, counting down

from compare match of TCNT3 and GRA3 and counting up when TCNT4 underflows. PWM

waveforms are output by repeated compare matches with each of the general registers in the

SH7021 Datasheet(PDF) 282 Page - Renesas Technology Corp