How to write pwm using picbasic pro?

[Haydn303]

How to write pwm using picbasic pro?

[longpole001]

heres an example that may be of value i found that i found usefull , its for the 18f1825 , it does not use all the pic pasic pro command set but if you just do a search on PWM on forum , you will soon find many examples

'	PWM_TEST.BAS
'
'	WRITTEN BY DAVID PUROLA 04/05/2012
'
'	WRITTEN FOR USE W/16F1825 E/P @ 32 Mhz.
'
'
DEFINE OSC 32
DEFINE NO_CLRWDT 1

#CONFIG
;----- CONFIG1 Options --------------------------------------------------
  __config _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_ON & _CLKOUTEN_OFF & _IESO_ON & _FCMEN_ON

;----- CONFIG2 Options --------------------------------------------------
  __config _CONFIG2, _WRT_OFF & _PLLEN_ON & _STVREN_ON & _BORV_19 & _LVP_OFF
#ENDCONFIG

' ********************************************************************
'				Declare Port Variables
' ********************************************************************
COMOUT		VAR	PORTA.0	'0-OUTPUT COMMUNICATIONS PORT PIN
COMIN		VAR	PORTA.1	'1-INPUT COMMUNICATIONS PORT PIN
FEEDBK	    VAR	PORTA.2	'1-ANALOG INPUT FROM POSITION POT
RST			VAR	PORTA.3	'1-RESET/MCLR
BATTERY		VAR	PORTA.4	'1-ANALOG INPUT FROM BATTERY VOLTAGE
RS485TX		VAR	LATA.5	'0-DRIVER ENABLE INPUT TO RS-485

RUNLED		VAR	LATC.0	'0-RUN LED
ESTOP		VAR	PORTC.1	'1-ESTOP INPUT FROM BUTTON
CWLIM	  	VAR	PORTC.2	'1-CW HARD LIMIT SWITCH
CCWLIM		VAR	PORTC.3	'1-CCW HARD LIMIT SWITCH
CCW			VAR	LATC.4	'0-PWM CCW OUTPUT
CW			VAR	LATC.5 '0-PWM CW OUTPUT

' ********************************************************************
'				Define Constants
' ********************************************************************
NREADS		CON	16		'A/D READINGS TO AVERAGE
MAXCHANNELS	CON	2		'NUMBER OF A/D CHANNELS
OFF_		CON	0		'DIGITAL 0 NUMONIC
ON_			CON	1       'DIGITAL 1 NUMONIC
SINK		CON	0		'MOTOR SINK CURRENT NUMONIC
SOURCE		CON	1		'MOTOR SOURCE CURRENT NUMONIC
SPAN		CON	2040	'WORKING VALUE SERVO FULL SCALE SPAN

' ********************************************************************
'		       Declare Variables
' ********************************************************************
BITSWORD	VAR	WORD BANK0	'BITS FOR STORAGE
TX_EMPTY    VAR BITSWORD.0	'TRANSMIT BUFFER EMPTY FLAG
RX_BUFFULL  VAR BITSWORD.1  'RECEIVER BUFFER FULL FLAG
RX_MESSAGE	VAR BITSWORD.2	'MESSAGE RECEIVED FLAG
COWS_HOME	VAR BITSWORD.3	'LOOP FLAG
MSBIT		VAR BITSWORD.4	'SIGN FLAG FOR MATH
MSGSTAT		VAR BITSWORD.5	'SIGN FLAG FOR CORRECT MESSAGE
TXPAR		VAR	BITSWORD.6	'PARITY ENABLE FLAG
PARITYTYPE	VAR BITSWORD.7	'PARITY TYPE (1=ODD/0=EVEN)

VOLTS	 	VAR	WORD[MAXCHANNELS]	'A/D READINGS (N-CHANNELS)
AV_VOLTS 	VAR	WORD[MAXCHANNELS]	'A/D READINGS (N-CHANNELS)
ADREADS 	VAR	WORD[NREADS * MAXCHANNELS]'A/D READINGS (0-65535) (N-CHANNELS * N-READS)
ADINDEX		VAR	BYTE[MAXCHANNELS]	'RING INDEX POINTER (N-CHANNELS)
CHANNEL		VAR	BYTE	'A/D CHANNEL VARIABLE

BITINDEX	VAR	BYTE	'SCRATCH VARIABLE
SCRATCH	    VAR	WORD	'SCRATCH VARIABLE WORD
JUNK	    VAR	BYTE	'SCRATCH VARIABLE
JUNK1	    VAR	BYTE	'SCRATCH VARIABLE
SCRATCH1	VAR	WORD	'SCRATCH VARIABLE WORD
DIR			VAR	BYTE	'DIRECTION BIT,BYTE PATERN FOR PWM STEERING LOGIC

FINAL		VAR	WORD	'FINAL EQUATION OUTPUT
HALFSPAN	VAR	WORD	'HALF SPAN ERROR LIMITER

' ********************************************************************
'				SYSTEM INITIALIZATION
' ********************************************************************
	clear
	PORTA = %00000000
	PORTC = %00000000
	TRISA = %00101110	'INITIALIZE PORT DIRECTIONS
	TRISC = %00000000	'INITIALIZE PORT DIRECTIONS
	
    OSCCON = %11110000	'SET SYSTEM CLOCK SWITCH BIT
   	
    INTCON = %00000000 'CLEAR GIE,PEIE,TMR0IE,INTE,RBIE,TMR0IF,INTF,RBIF
   	PIE1 = %00000000    'CLEAR ALL INTERRUPT ENABLE BITS
   	PIR1 = %00000000    'CLEAR ALL INTERRUPT FLAGS
  	
    PIE2 = %00000000    'CLEAR ALL INTERRUPT ENABLE BITS
  	PIR2 = %00000000    'CLEAR ALL INTERRUPT FLAGS
	
    APFCON0 = %10000100	'ENABLE USART ON PORTA.0:1
	APFCON1 = %00000000	'ALL DEFAULT
	
    ANSELA = %00010100	'AN2,AN4 ANALOG,:AN0,AN1 DIGITAL I/O
	WPUA = %00000000	'WEAK PULLUP'S OFF
	
    INLVLA = %00111111	'SCHMITT TRIGGER

	ANSELC = %00000000	'PORTC, DIGITAL I/O
	WPUC = %00000000	'WEAK PULLUP'S OFF

	INLVLC = %00111111	'SCHMITT TRIGGER
  	ADCON0 = %00000000  'CHS2:0,GO/DONE,ADOFF
  	ADCON1 = %11100000  'RIGHT JUSTIFIED,FOSC/64,VSS,VDD
	SRCON0 = %00000000
	SRCON1 = %00000000
   	CM1CON0 = %00000000	'CLEAR/DISABLE COMPARATOR
   	CM1CON1 = %00000000	'CLEAR/DISABLE COMPARATOR
   	CM2CON0 = %00000000	'CLEAR/DISABLE COMPARATOR
   	CM2CON1 = %00000000	'CLEAR/DISABLE COMPARATOR
  	CMOUT = %00000000	'DISABLE OUTPUT REGISTER
   	DACCON0 = %00000000	'CLEAR/DISABLE D/A
   	DACCON1 = %00000000	'CLEAR/DISABLE D/A
  	FVRCON = %00000000	'DISABLE FIXED VOLTAGE REFERENCE
   	
    OPTION_REG = %10000000 'CLEAR ALL PULL-UPS,INTEDG,T0CS,T0SE,PSA,PS
   	T1CON = %00010101	'PRESCALER 1/2,START TIMER 1
   	T1GCON = %00000000	'NO GATE CONTROL
   	
    T4CON = %00000000	'POSTSCALER 1/1,STOP,PRESCALER 1/1
   	T6CON = %00000000	'POSTSCALER 1/1,STOP,PRESCALER 1/1

   	T2CON = %00000110	'POSTSCALER 1/1,START,PRESCALER 16
	CCPTMRS = %00000000'SET COMPMPARES 1,2,3 FOR TIMER 2
   	TMR2 = 0			'CLEAR TMR2 MODULE REGISTER
   	PR2 = 255			'SET PERIOD ((((1 / 40,000,000)*4)*16 PRESCALE)*(1+255 PR2)) = 2.44 KHZ
   	CCP1CON = %00001100	'PLACE CCP1 INTO PWM MODE
   	CCPR1L = $00		'CLEAR CCP1 LOWER 8 BITS
   	CCPR1H = $00		'CLEAR CCP1 UPPER 2 BITS

   	CCP2CON = %00000000	'PLACE CCP1 INTO DISABLE MODE
   	CCP4CON = %00000000	'PLACE CCP1 INTO DISABLE MODE
   	TMR4 = 0			'CLEAR TMR2 MODULE REGISTER
   	TMR6 = 0			'CLEAR TMR2 MODULE REGISTER
   	PR4 = $FF			'SET PERIOD (1/1 PRESCALE * 256 PR2 * 1/20,000,000 * 4 = 19.53 Khz.
   	PR6 = $FF			'SET PERIOD (1/1 PRESCALE * 256 PR2 * 1/20,000,000 * 4 = 19.53 Khz.
   	CCPR2L = $00		'CLEAR LOWER 8 BITS
   	CCPR2H = $00		'CLEAR UPPER 2 BITS
   	CCPR3L = $00		'CLEAR LOWER 8 BITS
   	CCPR3H = $00		'CLEAR UPPER 2 BITS
   	CCPR4L = $00		'CLEAR LOWER 8 BITS
   	CCPR4H = $00		'CLEAR UPPER 2 BITS

	GOTO MAINLOOP

' ********************************************************************
'				SUBROUTINES
' ********************************************************************

'*********************************************************************
READAD:	'READ SYSTEM A/D VOLTAGES (AVERAGE 64 READINGS) 16F1825
'*********************************************************************
	ADCON0 = $01 | ((CHANNEL + 2) << 2)		' Set A/D to Channel X, On
	PAUSEUS 40
	VOLTS(CHANNEL) = 0     'CLEAR A/D READINGS
	SCRATCH = 0
	WHILE SCRATCH < 64     'SUM 64 READINGS
        ADCON0.1 = 1		' START CONVERSION
		WHILE ADCON0.1 = 1	'WAIT FOR A/D TO FINISH	
		WEND
        VOLTS(CHANNEL) = VOLTS(CHANNEL) + (((ADRESH & $3) << 8) + ADRESL)	'BUILD SENSOR WORD
		SCRATCH = SCRATCH + 1
	WEND
	VOLTS(CHANNEL) = VOLTS(CHANNEL) >> 5	'TURN INTO 11 BIT RESULT
	ADINDEX(CHANNEL) = (ADINDEX(CHANNEL) + 1) & (NREADS - 1)	'INCREMENT INDEX POINTER
	ADREADS((CHANNEL * (NREADS)) + ADINDEX(CHANNEL)) = VOLTS(CHANNEL)	'STORE IN RING BUFFER
	RETURN
	
'*********************************************************************
AVERAGE_AD:		'AVERAGE N X 16 BIT VALUES WO/LONG OR 32 BIT MATH
'*********************************************************************
	SCRATCH = 0 ' Zero to Start 
	SCRATCH1 = 0 
	JUNK = 0
	WHILE JUNK < NREADS
		SCRATCH = SCRATCH + ADREADS((CHANNEL * NREADS) + JUNK)
		If SCRATCH < ADREADS((CHANNEL * NREADS) + JUNK) then 
			SCRATCH1 = SCRATCH1 + 1	' Detect overflow and carry... 
		endif 
		JUNK = JUNK + 1
	WEND

	JUNK = ((NCD NREADS) - 1)
	SCRATCH = SCRATCH >> JUNK
	JUNK = JUNK - 1
	BITINDEX = 15
	WHILE JUNK < 255
		SCRATCH.0(BITINDEX) = SCRATCH1.0(JUNK)
		JUNK = JUNK - 1
		BITINDEX = BITINDEX - 1
	WEND
	AV_VOLTS(CHANNEL) = SCRATCH
	RETURN
	
' ********************************************************************
OUTPWM:		'OUTPUT NEW PWN VALUE
' ********************************************************************
	LATC.4 = SINK	'PRESET PORT PIN LOW
	LATC.5 = SINK	'PRESET PORT PIN LOW
	PSTR1CON = %00010000 | DIR	'1=CW (PWM P1A/STATIC STATE P1B, 2=CCW (PWM P1B/STATIC STATE P1A
	CCPR1L = FINAL >> 2	'UPDATE PWM1 UPPER 8 BITS
	CCP1CON = $0C | ((FINAL & $3) << 4)	'UPDATE PWM1 LOWER 2 BITS
	RETURN

' ********************************************************************
MAINLOOP:'				PROGRAM LOOP
' ********************************************************************
	HALFSPAN = SPAN / 2
	REPEAT
		CHANNEL = 0		'FEEDBACK POT
		GOSUB READAD	'READ SYSTEM A/D VOLTAGES (AVERAGE 64 READINGS)	
		GOSUB AVERAGE_AD	'AVERAGE N X 16 BIT VALUES WO/LONG OR 32 BIT MATH
		FINAL = VOLTS(0) - HALFSPAN
		DIR = FINAL.15
		DIR = 1 << DIR
		IF FINAL.15 = 1 THEN FINAL = ABS(FINAL)
		FINAL = FINAL MIN HALFSPAN
		GOSUB OUTPWM		'OUTPUT NEW PWN VALUE

	UNTIL COWS_HOME
' ********************************************************************
	END				'SHOULD NEVER GET HERE.........
	STOP

[electroken]

You didn't mention which type of PWM you wanted, HWPM for continous PWM, or regular. Here is a quickie program that flashes a LED from full bright to dimly lit. It's good for an indication of some kind.
Install a LED on portb.0

T var byte' set-up the loop variable
For t=1 to 20' amount of bright/dim  flashes
portb.0=1:pause 90:portb.0=0' full bright ON time then turn OFF---experiment with the ON time.
PWM portb.0,20,80' the 20 is LED brightness, the 80 is it's ON time--Again experiment with the numbers, try changing the 20 to 50.
TRISb=0' Once PWM is used on a pin, then that pin only wants PWM to be used. The TRISb resets the pin back to normal output.
next t' end of loop

If you had inputs on portb, like portb.1, and portb.2, then use TRISb=%00000110
.
While PWM is operating, nothing else is being done. Same way with SOUND. When using a servo, when PWM stops, the servo no longer gets data causing it to lose it's position if it was under a load. To correct this you would need to use the HWPM.
Hope this helped.
Electroken