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168 lines
4.7 KiB
168 lines
4.7 KiB
/**************************************************************************** |
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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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} |