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https://github.com/RIOT-OS/RIOT.git
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150 lines
3.5 KiB
C
150 lines
3.5 KiB
C
/*
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* Copyright (C) 2014 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser General
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* Public License v2.1. See the file LICENSE in the top level directory for more
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* details.
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*/
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/**
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* @ingroup lpc2387
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* @{
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*
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* @file
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* @brief CPU specific low-level PWM driver implementation for the LPC2387
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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*
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* @}
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*/
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#include "bitarithm.h"
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#include "lpc2387.h"
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#include "periph/pwm.h"
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#include "periph_conf.h"
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#define PCPWM1 BIT6
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/**
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* @note The PWM is always initialized with left-aligned mode.
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*
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* TODO: add center and right aligned modes
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*/
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int pwm_init(pwm_t dev, pwm_mode_t mode, unsigned int frequency, unsigned int resolution)
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{
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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/* select function PWM[3] for pins */
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PWM_0_PORT &= ~((3 << PWM_0_CH0_PIN * 2) |
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(3 << PWM_0_CH1_PIN * 2) |
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(3 << PWM_0_CH2_PIN * 2));
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PWM_0_PORT |= (PWM_0_FUNC << PWM_0_CH0_PIN * 2) |
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(PWM_0_FUNC << PWM_0_CH1_PIN * 2) |
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(PWM_0_FUNC << PWM_0_CH2_PIN * 2);
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/* power on PWM1 */
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PCONP |= BIT6;
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/* select PWM1 clock */
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PCLKSEL0 &= ~(BIT13);
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PCLKSEL0 |= (BIT12);
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/* reset PWM1s counter */
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PWM1TCR = BIT1;
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/* set prescaler */
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PWM1PR = (F_CPU / (frequency * resolution)) - 1;
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/* set match register */
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PWM1MR0 = resolution;
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PWM_0_CH0_MR = 0;
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PWM_0_CH1_MR = 0;
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PWM_0_CH2_MR = 0;
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/* reset timer counter on MR0 match */
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PWM1MCR = BIT1;
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/* enable PWM1 channel 3, 4 and 5 */
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PWM1PCR = (1 << (8 + PWM_0_CH0)) | (1 << (8 + PWM_0_CH1)) | (1 << (8 + PWM_0_CH2));
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/* enable PWM1 timer in PWM mode */
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PWM1TCR = BIT0 + BIT3;
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/* update match registers */
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PWM1LER = BIT0 | (1 << PWM_0_CH0) | (1 << PWM_0_CH1) | (1 << PWM_0_CH2);
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break;
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#endif
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case PWM_UNDEFINED:
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default:
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return -1;
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}
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return 0;
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}
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int pwm_set(pwm_t dev, int channel, unsigned int value)
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{
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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switch (channel) {
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case 0:
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PWM_0_CH0_MR = value;
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PWM1LER |= (1 << PWM_0_CH0);
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break;
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case 1:
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PWM_0_CH1_MR = value;
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PWM1LER |= (1 << PWM_0_CH1);
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break;
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case 2:
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PWM_0_CH2_MR = value;
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PWM1LER |= (1 << PWM_0_CH2);
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break;
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default:
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return -2;
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break;
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}
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break;
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#endif
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case PWM_UNDEFINED:
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default:
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return -1;
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}
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return 0;
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}
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int pwm_start(pwm_t dev)
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{
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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PCONP |= PCPWM1; /* enable PWM1 device */
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break;
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#endif
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case PWM_UNDEFINED:
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default:
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return -1;
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}
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return 0;
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}
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int pwm_stop(pwm_t dev)
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{
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switch (dev) {
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#if PWM_0_EN
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case PWM_0:
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PCONP &= ~PCPWM1; /* disable PWM1 device */
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break;
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#endif
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case PWM_UNDEFINED:
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default:
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return -1;
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}
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return 0;
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}
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