SH7101 datasheet(225/560 Pages) RENESAS

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Section 8 Multifunction Timer Pulse Unit (MTU)

Rev.1.00 Sep. 18, 2008 Page 191 of 522

REJ09B0069-0100

Counter value

TGRA_3

TCDR

TDDR

H'0000

TCNT_4

TCNTS

TCNT_3

TCNT_4

TCNTS

Time

Figure 8.34 Complementary PWM Mode Counter Operation

registers, buffer registers, and temporary registers. Figure 8.35 shows an example of

complementary PWM mode operation.

The registers which are constantly compared with the counters to perform PWM output are

TGRB_3, TGRA_4, and TGRB_4. When these registers match the counter, the value set in bits

OLSN and OLSP in the timer output control register (TOCR) is output.

The buffer registers for these compare registers are TGRD_3, TGRC_4, and TGRD_4.

Between a buffer register and compare register there is a temporary register. The temporary

registers cannot be accessed by the CPU.

Data in a compare register is changed by writing the new data to the corresponding buffer register.

The buffer registers can be read or written at any time.

The data written to a buffer register is constantly transferred to the temporary register in the Ta

interval. Data is not transferred to the temporary register in the Tb interval. Data written to a

buffer register in this interval is transferred to the temporary register at the end of the Tb interval.

The value transferred to a temporary register is transferred to the compare register when TCNTS

for which the Tb interval ends matches TGRA_3 when counting up, or H'0000 when counting

down. The timing for transfer from the temporary register to the compare register can be selected

with bits MD3 to MD0 in the timer mode register (TMDR). Figure 8.35 shows an example in

which the mode is selected in which the change is made in the trough.

In the Tb interval (Tb1 in figure 8.35) in which data transfer to the temporary register is not

performed, the temporary register has the same function as the compare register, and is compared

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