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126 lines
2.8 KiB
C
126 lines
2.8 KiB
C
/*
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* Copyright (C) 2014-2016 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_lpc23xx
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* @ingroup drivers_periph_pwm
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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 LPC23XX family
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*
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* The current implementation is somewhat limited: it supports only a single
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* hardware PWM device (fixed to PWM1) and it is fixed on supporting 3 channels.
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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 "cpu.h"
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#include "assert.h"
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#include "bitarithm.h"
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#include "periph/pwm.h"
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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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uint32_t pwm_init(pwm_t dev, pwm_mode_t mode, uint32_t freq, uint16_t res)
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{
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if ((dev != PWM_DEV(0)) && (mode != PWM_LEFT)) {
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return 0;
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}
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/* select function PWM[3] for pins */
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PWM_PORT &= ~((3 << PWM_CH0_PIN * 2) |
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(3 << PWM_CH1_PIN * 2) |
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(3 << PWM_CH2_PIN * 2));
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PWM_PORT |= (PWM_FUNC << PWM_CH0_PIN * 2) |
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(PWM_FUNC << PWM_CH1_PIN * 2) |
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(PWM_FUNC << PWM_CH2_PIN * 2);
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/* power on PWM1 */
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PCONP |= PCPWM1;
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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 = (CLOCK_CORECLOCK / (freq * res)) - 1;
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/* set match register */
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PWM1MR0 = res;
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PWM_CH0_MR = 0;
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PWM_CH1_MR = 0;
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PWM_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_CH0)) | (1 << (8 + PWM_CH1)) | (1 << (8 + PWM_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_CH0) | (1 << PWM_CH1) | (1 << PWM_CH2);
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return freq;
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}
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uint8_t pwm_channels(pwm_t dev)
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{
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(void)dev;
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assert(dev == PWM_DEV(0));
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return PWM_CHANNELS;
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}
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void pwm_set(pwm_t dev, uint8_t channel, uint16_t value)
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{
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(void)dev;
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assert((dev == PWM_DEV(0)) && (channel < 3));
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switch (channel) {
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case 0:
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PWM_CH0_MR = value;
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PWM1LER |= (1 << PWM_CH0);
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break;
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case 1:
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PWM_CH1_MR = value;
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PWM1LER |= (1 << PWM_CH1);
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break;
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case 2:
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PWM_CH2_MR = value;
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PWM1LER |= (1 << PWM_CH2);
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break;
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}
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}
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void pwm_poweron(pwm_t dev)
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{
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(void)dev;
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assert(dev == PWM_DEV(0));
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PCONP |= PCPWM1;
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PWM1TCR |= BIT0;
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}
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void pwm_poweroff(pwm_t dev)
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{
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(void)dev;
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assert(dev == PWM_DEV(0));
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PWM1TCR &= ~(BIT0);
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PCONP &= ~(PCPWM1);
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}
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