MC68HC705MC4 Datasheet, PDF (72/99 Pages) Motorola, Inc – Microcontrollers

MC68HC705MC4 Specification Rev. 1.5
9.7 PWM DURING STOP MODE
In STOP mode the oscillator is stopped causing the PWM to cease function. Any signal in
process is suspended in whatever phase the signal happens to be in. In the EPROM
device, the STOP instruction will be disabled.
9.8 APPLICATION EXAMPLES
The following examples demonstrate PWM configuration options to drive DC brush and
permanent magnet brushless motors. The schematic diagrams are simplified for clarity.
9.8.1 DC BRUSH MOTOR INTERFACE
The basic interface for a single DC brush motor is shown below.
B+
PA7
PA5
PA3
PWMA
A
PA1
T
- mask feature disabled
- PA1, PA3 drive PWM or logic 0
- PA5 and PA7 output ports
0V
Input
Capture
PD6
Figure 9-9: DC Brush Motor Interface
Table 9-2: DC Brush Motor Truth Table
Function
PA1
PA3
PA5
PA7
Forward
0
PWM
1
0
Reverse
PWM
0
0
1
Stop
0
0
1
1
PWM channel A is configured such that the PWM signal may be directed to either PA1
(CSA1=1) or PA3 (CSA2=1). When not driving the PWM signal, these ports should drive
a logic 0 (MEA=0, PA1=0, DDRA1=1, PA3=0, DDRA3=1). PA5 is configured as an output
Section 9: Pulse Width Modulator
MOTOROLA
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