forked from Archive/PX4-Autopilot
168 lines
4.7 KiB
C
168 lines
4.7 KiB
C
/****************************************************************************
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*
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* Copyright (C) 2012 PX4 Development Team. 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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name PX4 nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* 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 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file adc.c
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*
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* Simple ADC support for PX4IO on STM32.
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*/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <nuttx/arch.h>
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#include <arch/stm32/chip.h>
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#include <stm32_internal.h>
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#include <drivers/drv_hrt.h>
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#include <systemlib/perf_counter.h>
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#define DEBUG
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#include "px4io.h"
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/*
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* Register accessors.
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* For now, no reason not to just use ADC1.
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*/
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#define REG(_reg) (*(volatile uint32_t *)(STM32_ADC1_BASE + _reg))
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#define rSR REG(STM32_ADC_SR_OFFSET)
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#define rCR1 REG(STM32_ADC_CR1_OFFSET)
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#define rCR2 REG(STM32_ADC_CR2_OFFSET)
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#define rSMPR1 REG(STM32_ADC_SMPR1_OFFSET)
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#define rSMPR2 REG(STM32_ADC_SMPR2_OFFSET)
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#define rJOFR1 REG(STM32_ADC_JOFR1_OFFSET)
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#define rJOFR2 REG(STM32_ADC_JOFR2_OFFSET)
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#define rJOFR3 REG(STM32_ADC_JOFR3_OFFSET)
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#define rJOFR4 REG(STM32_ADC_JOFR4_OFFSET)
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#define rHTR REG(STM32_ADC_HTR_OFFSET)
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#define rLTR REG(STM32_ADC_LTR_OFFSET)
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#define rSQR1 REG(STM32_ADC_SQR1_OFFSET)
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#define rSQR2 REG(STM32_ADC_SQR2_OFFSET)
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#define rSQR3 REG(STM32_ADC_SQR3_OFFSET)
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#define rJSQR REG(STM32_ADC_JSQR_OFFSET)
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#define rJDR1 REG(STM32_ADC_JDR1_OFFSET)
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#define rJDR2 REG(STM32_ADC_JDR2_OFFSET)
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#define rJDR3 REG(STM32_ADC_JDR3_OFFSET)
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#define rJDR4 REG(STM32_ADC_JDR4_OFFSET)
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#define rDR REG(STM32_ADC_DR_OFFSET)
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perf_counter_t adc_perf;
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int
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adc_init(void)
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{
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adc_perf = perf_alloc(PC_ELAPSED, "adc");
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/* do calibration if supported */
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#ifdef ADC_CR2_CAL
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rCR2 |= ADC_CR2_RSTCAL;
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up_udelay(1);
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if (rCR2 & ADC_CR2_RSTCAL)
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return -1;
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rCR2 |= ADC_CR2_CAL;
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up_udelay(100);
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if (rCR2 & ADC_CR2_CAL)
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return -1;
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#endif
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/* arbitrarily configure all channels for 55 cycle sample time */
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rSMPR1 = 0b00000011011011011011011011011011;
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rSMPR2 = 0b00011011011011011011011011011011;
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/* XXX for F2/4, might want to select 12-bit mode? */
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rCR1 = 0;
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/* enable the temperature sensor / Vrefint channel if supported*/
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rCR2 =
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#ifdef ADC_CR2_TSVREFE
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/* enable the temperature sensor in CR2 */
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ADC_CR2_TSVREFE |
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#endif
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0;
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#ifdef ADC_CCR_TSVREFE
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/* enable temperature sensor in CCR */
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rCCR = ADC_CCR_TSVREFE;
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#endif
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/* configure for a single-channel sequence */
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rSQR1 = 0;
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rSQR2 = 0;
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rSQR3 = 0; /* will be updated with the channel each tick */
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/* power-cycle the ADC and turn it on */
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rCR2 &= ~ADC_CR2_ADON;
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up_udelay(10);
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rCR2 |= ADC_CR2_ADON;
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up_udelay(10);
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rCR2 |= ADC_CR2_ADON;
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up_udelay(10);
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return 0;
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}
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uint16_t
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adc_measure(unsigned channel)
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{
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perf_begin(adc_perf);
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/* clear any previous EOC */
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if (rSR & ADC_SR_EOC)
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rSR &= ~ADC_SR_EOC;
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/* run a single conversion right now - should take about 60 cycles (a few microseconds) max */
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rSQR3 = channel;
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rCR2 |= ADC_CR2_ADON;
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/* wait for the conversion to complete */
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hrt_abstime now = hrt_absolute_time();
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while (!(rSR & ADC_SR_EOC)) {
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/* never spin forever - this will give a bogus result though */
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if ((hrt_absolute_time() - now) > 1000) {
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debug("adc timeout");
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break;
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}
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}
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/* read the result and clear EOC */
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uint16_t result = rDR;
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perf_end(adc_perf);
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return result;
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} |