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9.5
Operation
A PWM waveform like the one shown in figure 9.2 is output from the PWX pin. Data in DADR
corresponds to the total width (T
when CFS = 0, 64 pulses when CFS = 1). When OS = 0, this waveform is directly output. When
OS = 1, the output waveform is inverted, and data in DADR value corresponds to the total width
(T
) of the high (1) output pulses. Figures 9.3 and 9.4 show the types of output waveform.
H
t
f
Base cycle
(T × 64 or T × 256)
t
L
Table 9.4 summarizes the relationships between the CKS and CFS bit settings and the resolution,
base cycle, and conversion cycle. The PWM output remains fixed unless the contents of DADR
are at least a certain minimum value. The relationship between the OS bit and the output
waveform is shown in figures 9.3 and 9.4.
) of the low (0) pulses output in one conversion cycle (256 pulses
L
1 conversion cycle
(T × 2
14
(= 16384))
Figure 9.2 PWMX (D/A) Operation
T: Resolution
m
= Σ t
T
(OS = 0)
L
Ln
n = 1
(When CFS = 0, m = 256
When CFS = 1, m = 64)
Rev. 1.00, 09/03, page 233 of 704
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