mc68hc705v12 Freescale Semiconductor, Inc, mc68hc705v12 Datasheet - Page 114

• Manufacturer Part Number: mc68hc705v12
• Description: M68hc05-based Mcu Hc05 Freescale Semiconductor
• Manufacturer: Freescale Semiconductor, Inc

Pulse Width Modulators (PWMs)
Advance Information
11.3 PWM Functional Description
The PWM is capable of generating signals from 0 percent to 100 percent
duty cycle. A $00 in the PWM data register yields a low output (0
percent), but a $3F yields a duty of 63/64. To achieve the 100 percent
duty (high output), the polarity control bit is set to 0 while the data register
has $00 in it.
When not in use, the PWM system can be shut off to save power by
clearing the clock rate select bits PSA0x and PSA1x in PWM control
registers.
Writes to the PWM data registers are buffered and can, therefore, be
performed at any time without affecting the output signal. When the
PWM subsystem is enabled, a write to the PWM control register will
become effective immediately.
When the PWM subsystem is enabled, a write to the PWM data register
will not become effective until the end of the current PWM period has
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OP
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Pulse Width Modulators (PWMs)
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1,
16
8,
Figure 11-1. PWM Block Diagram
RCLK
INTEGER DIVIDE
1–16
PWM CONTROL REGISTERS AND BUFFERS
SCLK
6-BIT COUNTER
MODULUS AND
COMPARATOR
PWM DATA
PWM DATA
REGISTER
BUFFER
( 64)
MC68HC705V12
PIN LOGIC
PWMx
—
Rev. 3.0
PWMx