Programmer's Model; Pwm Control Register - Motorola DragonBall MC68328 User Manual

Pulse Width Modulator
The prescaler provides operating flexibility. Figure 11-3 illustrates its functionality. The pres-
caler contains a variable divider that can divide the incoming clock by certain values
between 2 and 256.
DIV BY DIV BY
2 2

11.2 PROGRAMMER'S MODEL

This section describes the PWM module registers and control bits.

11.2.1 PWM Control Register

This register controls the overall PWM operation. Output pin status is also accessible.
15 14 13 12
PWM
IRQEN
IRQ
ADDRESS: $(FF)FFF500
PWMIRQ
This bit indicates that a period-compare posted an interrupt. Users can set this bit to im-
mediately post a PWM interrupt for debugging purposes. This bit automatically clears it-
self after it is read while set, eliminating an extra write cycle in the interrupt-service routine.
If the IRQEN bit is 0, this bit can be polled to indicate the status of the period comparator.
0 = No PWM period rollover
1 = PWM period rolled over
IRQEN
This bit controls the PWM interrupt. While this bit is low, the interrupt is disabled.
0 = PWM interrupt disabled
1 = PWM interrupt enabled
11-2 MC68328 DRAGONBALL PROCESSOR USER'S MANUAL
DIV BY DIV BY
DIV BY
2
2
Figure 11-3. PWM Prescaler
11 10 9 8
UNUSED LOAD
Figure 11-4. PWM Control Register
DIV BY
DIV BY
2 2
2
7 6 5
PIN 0 POL PWMEN
DIV BY
2
clk sel
clk sel
4 3 2 1
0 CLKSEL
Reset Value: $0000
MOTOROLA
0