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Pulse Width Modulator
11-4
MC68328 DRAGONBALL PROCESSOR USER’S MANUAL
MOTOROLA
CLKSEL
These bits select the output of the divider chain. The codings are
000 = Divide by 2
001 = Divide by 4
010 = Divide by 8
011 = Divide by 16
100 = Divide by 32
101 = Divide by 64
110 = Divide by 128
111 = Divide by 256
11.2.2 Period Register
This register controls the PWM period. When the counter value matches the value in this
register, an interrupt is posted and the counter is reset to start another period.
PERIOD
This is the value that resets the counter. There is one special case: when this register is
$00, the output is never set high (0% duty cycle).
11.2.3 Width Register
This register controls the pulse width. When the counter matches the value in this register,
the output is reset for the duration of the period. Note that if the value in this register is higher
than the period register, the output will never be reset, resulting in a 100% duty cycle.
WIDTH
When the counter reaches the value in this register, the output is reset.
11.2.4 Counter
This read-only register is the current count value and can be read at any time without dis-
turbing the counter.
COUNT
This is the current count value.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PERIOD
ADDRESS: $(FF)FFF502
Reset Value: 0000
Figure 11-5. Period Register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
WIDTH
ADDRESS: $(FF)FFF504
Reset Value: 0000
Figure 11-6. Width Register
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
COUNT
ADDRESS: $(FF)FFF506
Reset Value: 0000
Figure 11-7. Counter Register
Summary of Contents for DragonBall MC68328
Page 5: ...vi MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 25: ...Overview 1 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 45: ...System Integration Module 2 20 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 103: ...Parallel Ports 7 16 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 117: ...UART 8 14 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...
Page 127: ...SPI Master 10 6 MC68328 DRAGONBALL PROCESSOR USER S MANUAL MOTOROLA ...