Intel 8XC196MH User Manual
8XC196MC, MD, MH USER’S MANUAL
10-6
10.5 PROGRAMMING THE DUTY CYCLE
The values written to the PWMx_CONTROL and PWM_PERIOD registers control the width of
the high pulse, effectively controlling the duty cycle. The 8-bit value written to the control regis-
ter is loaded into a buffer, and this value is used during the next period. Use the following duty
cycle formula to calculate a desired duty cycle for given values of PWMx_CONTROL and
PWM_PERIOD, and then write these values to the appropriate registers.
the high pulse, effectively controlling the duty cycle. The 8-bit value written to the control regis-
ter is loaded into a buffer, and this value is used during the next period. Use the following duty
cycle formula to calculate a desired duty cycle for given values of PWMx_CONTROL and
PWM_PERIOD, and then write these values to the appropriate registers.
Duty Cycle (in %)
=
Pulsewidth (in µs)
=
where:
PWM
x
_CONTROL
=
8-bit value to load into the PWM
x
_CONTROL register
PWM_PERIOD
=
8-bit value to load into the PWM_PERIOD register
Pulsewidth
=
width of each high pulse
T
PWM
=
output period on the PWM pin, in
µ
s
PWM_PERIOD
Address:
Reset State:
1FB4H
00H
The PWM period (PWM_PERIOD) register controls the period of the PWM outputs. It contains a value
that determines the number of state counts necessary for incrementing the PWM counter. The value
of PWM_PERIOD is loaded into the PWM period count register whenever the count equals zero.
that determines the number of state counts necessary for incrementing the PWM counter. The value
of PWM_PERIOD is loaded into the PWM period count register whenever the count equals zero.
7
0
PWM Period
Bit
Number
Function
7:0
PWM Period
This register controls the period of the PWM outputs. The value of PWM_PERIOD is
loaded into the PWM period count register whenever the count equals zero.
loaded into the PWM period count register whenever the count equals zero.
Figure 10-3. PWM Period (PWM_PERIOD) Register
PWM
x
_C ON TRO L
PWM_PERIO D
1
+
-------------------------------------------------------
100
×
Duty Cycle
T
PWM
×
100
------------------------------------------------