//
// $Id: pwm.c 350 2009-01-12 01:25:46Z jcw $
// $Revision: 350 $
// $Author: jcw $
// $Date: 2009-01-11 20:25:46 -0500 (Sun, 11 Jan 2009) $
// $HeadURL: http://tinymicros.com/svn_public/arm/lpc2148_demo/trunk/pwm/pwm.c $
//
#include "FreeRTOS.h"
#include "pwm.h"
//
//
//
static int pwmPulseWidth = 20000;
static int pwmPercentage = 50;
//
//
//
int pwmDutyCycle (int percentage)
{
if ((percentage < 0) || (percentage > 100))
return -1;
PWM_MR5 = ((configCPU_CLOCK_HZ / pwmPulseWidth) * (pwmPercentage = percentage)) / 100;
PWM_LER = PWM_LER_M5L;
return 0;
}
//
//
//
int pwmPulseWidthInMicroseconds (int us)
{
unsigned int count = (configCPU_CLOCK_HZ / 1000000) * us;
if (count > PWM_MR0)
return -1;
PWM_MR5 = count;
PWM_LER = PWM_LER_M5L;
return 0;
}
//
//
//
int pwmFrequency (int frequency)
{
if ((frequency < 1) || (frequency >= (int) configCPU_CLOCK_HZ))
return -1;
PWM_MR0 = (configCPU_CLOCK_HZ / (pwmPulseWidth = frequency));
PWM_MR5 = ((configCPU_CLOCK_HZ / pwmPulseWidth) * pwmPercentage) / 100;
PWM_LER = PWM_LER_M5L | PWM_LER_M0L;
return 0;
}
//
//
//
void pwmInit (void)
{
SCB_PCONP |= SCB_PCONP_PCPWM0;
PCB_PINSEL1 = (PCB_PINSEL1 & ~PCB_PINSEL1_P021_MASK) | PCB_PINSEL1_P021_PWM5;
PWM_TCR = PWM_TCR_CR;
PWM_PR = 0;
PWM_MR0 = (configCPU_CLOCK_HZ / pwmPulseWidth);
PWM_MCR |= PWM_MCR_MR0R;
PWM_PCR |= PWM_PCR_ENA5;
PWM_TCR = (PWM_TCR_CE | PWM_TCR_PWME);
pwmDutyCycle (50);
}
