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