SH7101 datasheet(216/486 Pages) RENESAS

216 / 486 page

8. Multi-Function Timer Pulse Unit (MTU)

Rev.2.00 Sep. 27, 2007 Page 182 of 448

REJ09B0394-0200

The positive phase/negative phase off timing is generated by a compare-match with the solid-line

counter, and the on timing by a compare-match with the dotted-line counter operating with a delay

of the dead time behind the solid-line counter. In the T1 period, compare-match a that turns off the

negative phase has the highest priority, and compare-matches occurring prior to a are ignored. In

the T2 period, compare-match c that turns off the positive phase has the highest priority, and

compare-matches occurring prior to c are ignored.

In normal cases, compare-matches occur in the order a

→ b → c → d (or c → d → a' → b'), as

shown in figure 8.40.

If compare-matches deviate from the a

→ b → c → d order, since the time for which the negative

phase is off is less than twice the dead time, the figure shows the positive phase is not being turned

on. If compare-matches deviate from the c

→ d → a' → b' order, since the time for which the

positive phase is off is less than twice the dead time, the figure shows the negative phase is not

being turned on.

If compare-match c occurs first following compare-match a, as shown in figure 8.41, compare-

match b is ignored, and the negative phase is turned off by compare-match d. This is because

turning off of the positive phase has priority due to the occurrence of compare-match c (positive

phase off timing) before compare-match b (positive phase on timing) (consequently, the waveform

does not change since the positive phase goes from off to off).

Similarly, in the example in figure 8.42, compare-match a' with the new data in the temporary

off the positive phase, are ignored. As a result, the positive phase is not turned on.

Thus, in complementary PWM mode, compare-matches at turn-off timings take precedence, and

turn-on timing compare-matches that occur before a turn-off timing compare-match are ignored.

SH7101 Datasheet(PDF) 216 Page - Renesas Technology Corp