mc68hc908bd48 Freescale Semiconductor, Inc, mc68hc908bd48 Datasheet - Page 147

• Manufacturer Part Number: mc68hc908bd48
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

11.1 Contents
11.2 Introduction
11.3 Functional Description
MC68HC908BD48
Freescale Semiconductor
Data Sheet — MC68HC908BD48
—
Rev. 2.1
11.2
11.3
11.4
11.4.1
11.4.2
Sixteen 8-bits PWM channels are available on the MC68HC908BD48.
Channels 0 to 7 are shared with port-B I/O pins under the control of the
PWM control register 1. Channels 8 to 15 are shared with port-A I/O pins
under the control of the PWM control register 2.
Each 8-bit PWM channel is composed of an 8-bit register which contains
a 5-bit PWM in MSB portion and a 3-bit binary rate multiplier (BRM) in
LSB portion. There are 16 PWM data registers as shown in
The value programmed in the 5-bit PWM portion will determine the pulse
length of the output. The clock to the 5-bit PWM portion is the system
clock, the repetition rate of the output is hence 187.5KHz at 6MHz clock.
The 3-bit BRM will generate a number of narrow pulses which are
equally distributed among an 8-PWM-cycle frame. The number of pulses
generated is equal to the number programmed in the 3-bit BRM portion.
Examples of the waveforms are shown in
Section 11. Pulse Width Modulator (PWM)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
PWM Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147
PWM Data Registers 0 to 15 (0PWM–15PWM). . . . . . . . . 150
PWM Control Registers 1 and 2 (PWMCR1:PWMCR2) . . 151
Pulse Width Modulator (PWM)
Figure
11-3.
Table
Data Sheet
11-1.
147