Syntax:
HPWM_CCPTimerN channel, frequency, duty cycle [, timer 2, 4 or 6 ]
Command Availability:
Only available on Microchip PIC microcontrollers with Capture/Compare/PWM (CCP) module.
This command supports the CCP 8 bit support with selectable Timer 2, 4 or 6 only for CCP/PWM only.
For CCP/PWM support for timers 2 only see HPWM CCPTimer
Explanation:
This command sets up the hardware PWM module of the Microchip PIC microcontroller to generate
a PWM waveform of the given frequency and duty cycle.
If you only need one particular frequency and duty cycle, you should use PWMOn and the constants PWM_Freq and PWM_Duty instead.
channel is 1, 2, 3, 4 or 5, and corresponds to the pins CCP1, CCP2, CCP3, CCP4 and CCP5
respectively. On chips with only one CCP port, pin CCP or CCP1 is always
used, and channel is ignored. (It should be set to 1 anyway to allow
for future upgrades to more powerful microcontrollers.)
frequency sets the frequency of the PWM output. It is measured in KHz.
The maximum value allowed is 255 KHz. The minimum value varies depending
on the clock speed. 1 KHz is the minimum on chips 16 MHz or under and 2
Khz is the lowest possible on 20 MHz chips. In situations that do not
require a specific PWM frequency, the PWM frequency should equal
approximately 1 five-hundredth the clock speed of the microcontroller (ie 40 Khz on
a 20 MHz chip, 16 KHz on an 8 MHz chip). This gives the best duty cycle
resolution possible.
duty cycle specifies the desired duty cycle of the PWM signal, and
ranges from 0 to 255 where 255 is 100% duty cycle.
timer specifies the timer source. Timers 2, 4 and 6 are supported.
To stop the PWM signal use the HPWMOff method with the parameter of the channel.
'Stop the CCP/PWM signal
HPWMOff ( 1 )Example:
#chip 16F1825, 4
DIR portc Out
DIR porta Out
initialisation:
'Command as follows:
' HPWM_CCPTimerN CCP_Channel, Frequency, Duty, Timer Source. Timer source defaults to timer 2, so, the timersource is optional.
HPWM_CCPTimerN 3, 30, 77 , 4 'CCP/PWM module 3 using timer 4
HPWM_CCPTimerN 4, 40, 102, 6 'CCP/PWM module 4 using timer 6
HPWM 1, 10, 26 'CCP/PWM module 1 with no parameter therefore timer 2
do
loop