Datasheet

Table Of Contents
Section 19 14-Bit PWM
Rev. 2.00 Jul. 04, 2007 Page 437 of 692
REJ09B0309-0200
19.4.2 Setting for Pulse-Division Type PWM Operation
When using the pulse-division type PWM, set the registers in this sequence:
1. In accord with the PWM channel to be used, set the PWM1, PWM2, PWM3, or PWM4 bit (the
former two bits are in PMR9 and the latter two in PFCR) to 1 to specify the P90/PWM1,
P91/PWM2, P92/IRQ4/PWM3, or P93/PWM4 pin, respectively, to function as a PWM output
pin.
2. Set PWCR to select a conversion period.
3. Set the data for output waveform in PWDR. When the data is written to PWDR, the contents
are latched in the PWM waveform generator, and the PWM waveform generation data is
updated.
19.4.3 Operation of Pulse-Division Type PWM
One conversion period consists of 64 pulses, as shown in figure 19.3. The total high-level width
during this period (T
H
) corresponds to the data in PWDR. This relation is given in table 19.2.
t
f1
t
H1
T
H
=
t
H1
+
t
H2
+
t
H3
+ . . .
t
H64
t
f1
=
t
f2
=
t
f3
. . . =
t
H64
t
f2
t
f63
One conversion period
t
f64
t
H2
t
H3
t
H63
t
H64
Figure 19.3 Waveform Output by PWM