SH7041A datasheet(395/923 Pages) RENESAS

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Outline of Complementary PWM Mode Operation: In complementary PWM mode, 6-phase

PWM output is possible. Figure 12.39 illustrates counter operation in complementary PWM

mode, and figure 12.40 shows an example of complementary PWM mode operation.

• Counter operation

In complementary PWM mode, three counters—TCNT3, TCNT4, and TCNTS—perform

up/down-count operations.

TCNT3 is automatically initialized to the value set in TDDR when complementary PWM

mode is selected and the CST bit in TSTR is 0.

When the CST bit is set to 1, TCNT3 counts up to the value set in TGR3A, then switches to

down-counting when it matches TGR3A,. When the TCNT3 value matches TDDR, the counter

switches to up-counting, and the operation is repeated in this way.

TCNT4 is initialized to H'0000.

When the CST bit is set to 1, TCNT4 counts up in synchronization with TCNT3, and switches

to down-counting when it matches TCDR . On reaching H'0000, TCNT4 switches to up-

counting, and the operation is repeated in this way.

TCNTS is a read-only counter. It need not be initialized.

When TCNT3 matches TCDR during TCNT3 and TCNT4 up/down-counting, down-counting

is started, and when TCNTS matches TCDR, the operation switches to up-counting. When

TCNTS matches TGR3A, it is cleared to H'0000.

When TCNT4 matches TDDR during TCNT3 and TCNT4 down-counting, up-counting is

started, and when TCNTS matches TDDR, the operation switches to down-counting. When

TCNTS reaches H'0000, it is set with the value in TGR3A.

TCNTS is compared with the compare register and temporary register in which the PWM duty

is set during the count operation only.

Counter value

TGR3A

TCDR

TDDR

H'0000

TCNT4

TCNTS

TCNT3

TCNT4

TCNTS

Time

Figure 12.39 Complementary PWM Mode Counter Operation

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