88 lines
2.8 KiB
C
88 lines
2.8 KiB
C
/*****************************************************************************
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* Copyright (C) 2008
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* ProbeStar Telematics, LLC
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* All Rights Reserved. Proprietary and Confidential.
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*============================================================================
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* PWM Output
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*----------------------------------------------------------------------------
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* Output PWM (8 bit resolution for now)
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*****************************************************************************/
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/*****************************************************************************
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* includes
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*****************************************************************************/
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#include "system.h"
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#include "delay.h"
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#include "pwm.h"
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/*****************************************************************************
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* defines
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*****************************************************************************/
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/*****************************************************************************
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* macros
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*****************************************************************************/
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/*****************************************************************************
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* structs & typedefs
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*****************************************************************************/
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/*****************************************************************************
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* global constants
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*****************************************************************************/
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/*****************************************************************************
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* global variables
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*****************************************************************************/
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/*****************************************************************************
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* static constants
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*****************************************************************************/
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/*****************************************************************************
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* static variables
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*****************************************************************************/
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/*****************************************************************************
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* static prototypes
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*****************************************************************************/
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/*****************************************************************************
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* C functions
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*****************************************************************************/
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void PwmInit( void )
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{
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RC1 = RC2 = 0;
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PR2 = 255; // max period
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T2CON = 0b00000111; // 16:1 prescale
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// PWM1
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TRISC1 = 0;
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CCPR1L = 0;
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CCP1CON = 0b00001100;
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// PMW2
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TRISC2 = 0;
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CCPR2L = 0;
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CCP2CON = 0b00001100;
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}
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// duty cycle 0-PWM_DUTY_MAX (use macro)
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void PwmOut( BYTE byPin, WORD wDuty )
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{
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// clip
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if ( wDuty > PWM_DUTY_MAX )
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wDuty = PWM_DUTY_MAX;
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// allows custom rate for timer 2
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if ( PR2 != 255 )
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wDuty = wDuty * PR2 / PWM_DUTY_CYCLE;
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// scale duty cycle
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if ( byPin == 1 )
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CCPR1L = wDuty;
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if ( byPin == 2 )
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CCPR2L = wDuty;
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}
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