mc68331cpv20b1 Freescale Semiconductor, Inc, mc68331cpv20b1 Datasheet - Page 173

• Manufacturer Part Number: mc68331cpv20b1
• Description: Mc68331 32 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

7.11 Pulse-Width Modulation Unit
MC68331
USER’S MANUAL
PCLK
The pulse-width modulation (PWM) unit has two output channels, PWMA and PWMB.
A single clock output from the prescaler multiplexer drives a 16-bit counter that is used
to control both channels. Figure 7-6 is a block diagram of the pulse-width modulation
unit.
The PWM unit has two operational modes. Fast mode uses a clocking rate equal to 1/
256 of the prescaler output rate; slow mode uses a rate equal to 1/32768 of the pres-
caler output rate. The duty cycle ratios of the two PWM channels can be individually
controlled by software. The PWMA pin can also output the clock that drives the PWM
counter. PWM pins can also be used as output pins.
PAI
CAPTURE/COMPARE CLK
PRESCALER 512
TCNT OVERFLOW
SYNCHRONIZER
DIGITAL FILTER
Figure 7-5 Pulse Accumulator Block Diagram
PACTL
&
Freescale Semiconductor, Inc.
For More Information On This Product,
MUX
TMSK2
DETECT
LOGIC
EDGE
GENERAL-PURPOSE TIMER
Go to: www.freescale.com
MUX
2:1
INTERNAL
DATA BUS
OVERFLOW
ENABLE
TFLG2
8-BIT COUNTER
PACNT
INTERRUPT
REQUESTS
10
11
16/32 PLS ACC BLOCK
7-15
7