Hittade detta exempel, inte rakt på sak men kanske en bit påvägen att använda HPWM iallafall... det kanske hoppar "inom" denna programkod och inte kommer vidare ändå?
' PicBasic Pro Program to demonstrate hardware PWM.
' Output is a 1Khz signal with duty cycle sweeping
' from 20% to 80% once per second
' Note: PWM output will be on the CCP1 pin. Register
' names are for the PIC16F87x devices.
' PR2 = Timer2 period register, controls PWM period.
' CCPR1L and CCP1CON<5:4>bits control the duty cycle,
' and should be treated as a 10-bit word.
' Fosc = Clock Frequency (4MHz)
' PS = Timer2 Prescale Value (T2CON<1:0>)
' Freq = PWM output frequency
' Duty% = Duty cycle (20% = 0.2)
' formulas:
' PR2=(Fosc/(4*PS*Freq))-1
' CCPR1L:CCP1CON<5:4>=(PR2+1)*4*Duty%
dutyVARWORD' Duty cycle value (CCPR1L:CCP1CON<5:4>)
TRISC.2 = 0' Set PORTC.2 (CCP1) to output
CCP1CON = %00001100' Set CCP1 to PWM
T2CON = %00000101' Turn on Timer2, Prescale=4
' Use formula to determine PR2 value for a 1KHz signal,
' 4MHz clock, and prescale=4. (4E6/(4*4*1E3))-1=249
PR2 = 249' Set PR2 to get 1KHz out
' Use formula to determine CCPR1L:CCP1CON<5:4> value for
' ends of range 20% to 80%. (249+1)*4*0.2=200 (20% value)
' (249+1)*4*0.8=800 (80% value)
duty = 200' Set duty cycle to 20%
loop:CCP1CON.4 = duty.0' Store duty to registers as
CCP1CON.5 = duty.1' a 10-bit word
CCPR1L = DUTY >> 2
duty = duty + 10' Increase duty cycle
' Since the total sweep of duty is 600 (800-200) and
' we are adding 10 for each loop, that results in 60
' steps min to max. 1 second divided by 60 = 16.67mS
Pause 17' Pause 1/60 of second
IF (duty < 800) Then loop' Do it again unless 80% duty cycle
duty = 200' Reset to 20% duty cycle
GoTo loop' Do it forever
Eller saxat från ett annat forum..
I tried the suggested PWM built in PBP and it works pretty good.
Here is the code I used to get a nice ramp up and down even with
high brightness LEDs which are harder to control linearly.
led VAR PORTB.5
steps VAR WORD
cycles CON 2
' Change limits for steps to play around 0 or 100% brightness
' Change steps for different duration of ramps
' Works good even with high brightness LEDs, harder to control linearly
fade:
up:
For steps=0 TO 255
PWM led,steps,cycles
Next
High led
Pause 2500
down:
For steps=255 TO 1 STEP -1
PWM led,steps,cycles
Next
Low led
Pause 2500
GoTo fade
End
Det måste ju saknas en massa från det sista exemplet men det såg inte jätte tokigt ut iallafall
det var nästan at tjag hajade det
PIC kör koden från början till slut och om igen hela tiden? korrekt?
