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Section 13 14-bit Pulse Width Modulator (PWM)
13.1
Overview
The H8/3637 Series is provided with a 14-bit pulse width modulator (PWM). The PWM can be
used as a D/A converter by connecting a low-pass filter.
13.1.1
Features
Features of the 14-bit PWM are given below.
•
Choice of two conversion periods
•
A conversion period of 32,768/ø with a minimum transition width of 2/ø, or a conversion
period of 16,384/ø with a minimum transition width of 1/ø, can be selected.
•
Pulse-division method to reduce ripple
13.1.2
Block Diagram
Figure 13.1 shows a block diagram of the 14-bit PWM.
Internal data bus
PWDRL
PWDRU
PWCR
PWM
waveform
generator
ø/2
ø/4
Legend:
PWDRL:
PWDRU:
PWCR:
PWM data register L
PWM data register U
PWM control register
PWM
Figure 13.1 14-Bit PWM Block Diagram