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127 lines
2.7 KiB
C
127 lines
2.7 KiB
C
/*
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* Copyright (C) 2015 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 cpu_lpc11u34
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* @{
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*
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* @file
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* @brief Low-level ADC driver implementation
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*
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* @author Paul RATHGEB <paul.rathgeb@skynet.be>
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*
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* @}
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*/
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#include <stdint.h>
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#include <string.h>
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#include "cpu.h"
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#include "periph/adc.h"
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#include "periph_conf.h"
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/* guard in case that no ADC device is defined */
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#if ADC_NUMOF
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static inline uint32_t *_adc_channel_to_pin(int channel)
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{
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return (channel < 6) ? ((uint32_t*)(LPC_IOCON) + (11 + channel))
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: ((uint32_t*)(LPC_IOCON) + (16 + channel));
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}
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int adc_init(adc_t dev, adc_precision_t precision)
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{
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adc_poweron(dev);
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/* Set resolution */
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switch (precision) {
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case ADC_RES_6BIT:
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LPC_ADC->CR |= (0x04 << 17);
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break;
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case ADC_RES_8BIT:
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LPC_ADC->CR |= (0x02 << 17);
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break;
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case ADC_RES_10BIT:
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LPC_ADC->CR |= (0x0 << 17);
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break;
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case ADC_RES_12BIT:
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case ADC_RES_14BIT:
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case ADC_RES_16BIT:
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/* Resolution > 10 bits unsupported */
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adc_poweroff(dev);
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return -1;
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break;
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}
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/* ADC frequency : 3MHz */
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LPC_ADC->CR |= (15 << 8);
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return 0;
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}
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int adc_sample(adc_t dev, int channel)
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{
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if (channel > ADC_MAX_CHANNELS) {
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return -1;
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}
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/* Compute the IOCON register for the channel */
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uint32_t *cfg = _adc_channel_to_pin(channel);
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/* Put the pin in its ADC alternate function */
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if (channel < 5) {
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*cfg |= 2;
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}
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else {
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*cfg |= 1;
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}
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/* Configure ADMODE in analog input */
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*cfg &= ~(1 << 7);
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/* Start a conversion */
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LPC_ADC->CR |= (1 << channel) | (1 << 24);
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/* Wait for the end of the conversion */
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while (!(LPC_ADC->DR[channel] & (1 << 31)));
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/* Read and return result */
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return (LPC_ADC->DR[channel] >> 6);
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}
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void adc_poweron(adc_t dev)
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{
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switch (dev) {
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#if ADC_0_EN
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case ADC_0:
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LPC_SYSCON->PDRUNCFG &= ~(1 << 4);
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LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 13);
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break;
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#endif
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}
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}
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void adc_poweroff(adc_t dev)
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{
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switch (dev) {
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#if ADC_0_EN
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case ADC_0:
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LPC_SYSCON->PDRUNCFG |= (1 << 4);
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LPC_SYSCON->SYSAHBCLKCTRL &= ~(1 << 13);
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break;
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#endif
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}
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}
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int adc_map(adc_t dev, int value, int min, int max)
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{
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return 0;
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}
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float adc_mapf(adc_t dev, int value, float min, float max)
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{
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return 0.0;
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}
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#endif /* ADC_NUMOF */
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