PWM LPC17xxx

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/****************************************Copyright (c)****************************************************
** http://www.PowerAVR.com
** http://www.PowerMCU.com
**--------------File Info---------------------------------------------------------------------------------
** File name: pwm.c
** Last modified Date: 2010-05-12
** Last Version: V1.00
** Descriptions:
**
**--------------------------------------------------------------------------------------------------------
** Created by: PowerAVR
** Created date: 2010-05-10
** Version: V1.00
** Descriptions: 编写示例代码
**
**--------------------------------------------------------------------------------------------------------
*********************************************************************************************************/
#include "lpc17xx.h"
#include "pwm.h"

volatile uint32_t match_counter0, match_counter1;

/******************************************************************************
** Function name: PWM1_IRQHandler
**
** Descriptions: PWM1 interrupt handler
** For now, it only deals with PWM1 match 0
**
** parameters: None
** Returned value: None
**
******************************************************************************/
void PWM1_IRQHandler (void)
{
uint32_t regVal;

regVal = LPC_PWM1->IR;
if ( regVal & MR0_INT )
{
match_counter1++;
}
LPC_PWM1->IR |= regVal; /* clear interrupt flag on match 0 */
return;
}

/******************************************************************************
** Function name: PWM_Init
**
** Descriptions: PWM initialization, setup all GPIOs to PWM0~6,
** reset counter, all latches are enabled, interrupt
** on PWMMR0, install PWM interrupt to the VIC table.
**
** parameters: ChannelNum, Duty cycle
** Returned value: true or fase, if VIC table is full, return false
**
******************************************************************************/
uint32_t PWM_Init( uint32_t ChannelNum, uint32_t cycle )
{

if ( ChannelNum == 1 )
{
match_counter1 = 0;
LPC_PINCON->PINSEL4 = 0x00001555; /* set GPIOs for all PWM pins on PWM0 */

LPC_PWM1->TCR = TCR_RESET; /* Counter Reset */
LPC_PWM1->PR = 0x00; /* count frequency:Fpclk */
LPC_PWM1->MCR = PWMMR0I; /* interrupt on PWMMR0, reset on PWMMR0, reset
TC if PWM0 matches */
LPC_PWM1->MR0 = cycle; /* set PWM cycle */
LPC_PWM1->MR1 = cycle * 5/6;
LPC_PWM1->MR2 = cycle * 2/3;
LPC_PWM1->MR3 = cycle * 1/2;
LPC_PWM1->MR4 = cycle * 1/3;
LPC_PWM1->MR5 = cycle * 1/6;
LPC_PWM1->MR6 = 0;

/* all PWM latch enabled */
LPC_PWM1->LER = LER0_EN | LER1_EN | LER2_EN | LER3_EN | LER4_EN | LER5_EN | LER6_EN;
}
else
{
return ( 0 ); /* Unknown channel number */
}

NVIC_EnableIRQ(PWM1_IRQn);
return (1);
}

/******************************************************************************
** Function name: PWM_Set
**
** Descriptions: PWM cycle setup
**
** parameters: Channel number, PWM cycle, and offset
** Returned value: None
**
******************************************************************************/
void PWM_Set( uint32_t ChannelNum, uint32_t cycle, uint32_t offset )
{
if ( ChannelNum == 1 )
{
LPC_PWM1->MR0 = cycle; /* set PWM cycle */
LPC_PWM1->MR1 = cycle * 5/6 + offset;
LPC_PWM1->MR2 = cycle * 2/3 + offset;
LPC_PWM1->MR3 = cycle * 1/2 + offset;
LPC_PWM1->MR4 = cycle * 1/3 + offset;
LPC_PWM1->MR5 = cycle * 1/6 + offset;
LPC_PWM1->MR6 = offset;

/* The LER will be cleared when the Match 0 takes place, in order to
load and execute the new value of match registers, all the PWMLERs need to
reloaded. all PWM latch enabled */
LPC_PWM1->LER = LER0_EN | LER1_EN | LER2_EN | LER3_EN | LER4_EN | LER5_EN | LER6_EN;
}
return;
}

/******************************************************************************
** Function name: PWM_Start
**
** Descriptions: Enable PWM by setting the PCR, PTCR registers
**
** parameters: channel number
** Returned value: None
**
******************************************************************************/
void PWM_Start( uint32_t channelNum )
{
if ( channelNum == 1 )
{
/* All single edge, all enable */
LPC_PWM1->PCR = PWMENA1 | PWMENA2 | PWMENA3 | PWMENA4 | PWMENA5 | PWMENA6;
LPC_PWM1->TCR = TCR_CNT_EN | TCR_PWM_EN; /* counter enable, PWM enable */
}
return;
}

/******************************************************************************
** Function name: PWM_Stop
**
** Descriptions: Stop all PWM channels
**
** parameters: channel number
** Returned value: None
**
******************************************************************************/
void PWM_Stop( uint32_t channelNum )
{
if ( channelNum == 1 )
{
LPC_PWM1->PCR = 0;
LPC_PWM1->TCR = 0x00; /* Stop all PWMs */
}
return;
}

/******************************************************************************
** End Of File
******************************************************************************/

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神马意思？？？