99 lines
3.5 KiB
C
99 lines
3.5 KiB
C
/*
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* Copyright (c) 2013, ADVANSEE - http://www.advansee.com/
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* Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \addtogroup cc2538-adc
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* @{
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*
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* \file
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* Implementation of the cc2538 ADC driver
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*/
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#include "contiki.h"
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#include "dev/soc-adc.h"
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#include "dev/cctest.h"
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#include "dev/rfcore-xreg.h"
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#include "dev/adc.h"
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#include "reg.h"
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#include <stdint.h>
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/*---------------------------------------------------------------------------*/
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void
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adc_init(void)
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{
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/* Start conversions only manually */
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REG(SOC_ADC_ADCCON1) |= SOC_ADC_ADCCON1_STSEL;
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}
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/*---------------------------------------------------------------------------*/
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int16_t
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adc_get(uint8_t channel, uint8_t ref, uint8_t div)
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{
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uint32_t cctest_tr0, rfcore_xreg_atest;
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int16_t res;
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/* On-chip temperature sensor */
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if(channel == SOC_ADC_ADCCON_CH_TEMP) {
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/* Connect the temperature sensor to the ADC */
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cctest_tr0 = REG(CCTEST_TR0);
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REG(CCTEST_TR0) = cctest_tr0 | CCTEST_TR0_ADCTM;
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/* Enable the temperature sensor */
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rfcore_xreg_atest = REG(RFCORE_XREG_ATEST);
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REG(RFCORE_XREG_ATEST) = (rfcore_xreg_atest & ~RFCORE_XREG_ATEST_ATEST_CTRL) |
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RFCORE_XREG_ATEST_ATEST_CTRL_TEMP;
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}
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/* Start a single extra conversion with the given parameters */
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REG(SOC_ADC_ADCCON3) = (REG(SOC_ADC_ADCCON3) &
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~(SOC_ADC_ADCCON3_EREF | SOC_ADC_ADCCON3_EDIV | SOC_ADC_ADCCON3_ECH)) |
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ref | div | channel;
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/* Poll until end of conversion */
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while(!(REG(SOC_ADC_ADCCON1) & SOC_ADC_ADCCON1_EOC));
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/* Read conversion result, reading SOC_ADC_ADCH last to clear
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* SOC_ADC_ADCCON1.EOC */
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res = REG(SOC_ADC_ADCL) & 0xfc;
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res |= REG(SOC_ADC_ADCH) << 8;
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/* On-chip temperature sensor */
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if(channel == SOC_ADC_ADCCON_CH_TEMP) {
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/* Restore the initial temperature sensor state and connection (better for
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* power consumption) */
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REG(RFCORE_XREG_ATEST) = rfcore_xreg_atest;
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REG(CCTEST_TR0) = cctest_tr0;
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}
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/* Return conversion result */
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return res;
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}
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/** @} */
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