mirror of https://github.com/ArduPilot/ardupilot
89 lines
2.1 KiB
C++
89 lines
2.1 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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analog capture for IOMCU. This uses direct register access to avoid
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using up a DMA channel and to minimise latency. We capture a single
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sample at a time
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*/
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#include "ch.h"
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#include "hal.h"
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#include "analog.h"
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#if HAL_USE_ADC != TRUE
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#error "HAL_USE_ADC must be set"
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#endif
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/*
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initialise ADC capture
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*/
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void adc_init(void)
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{
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adc_lld_init();
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rccEnableADC1(true);
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/* set channels 4 and 5 for 28.5us sample time */
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ADC1->SMPR2 = ADC_SMPR2_SMP_AN4(ADC_SAMPLE_28P5) | ADC_SMPR2_SMP_AN5(ADC_SAMPLE_28P5);
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/* capture a single sample at a time */
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ADC1->SQR1 = 0;
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ADC1->SQR2 = 0;
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}
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/*
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capture one sample on a channel
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*/
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static uint16_t adc_sample_channel(uint32_t channel)
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{
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// clear EOC
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ADC1->SR = 0;
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/* capture one sample */
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ADC1->SQR3 = channel;
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ADC1->CR2 |= ADC_CR2_ADON;
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/* wait for the conversion to complete */
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uint32_t counter = 16;
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while (!(ADC1->SR & ADC_SR_EOC)) {
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if (--counter == 0) {
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// ensure EOC is clear
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ADC1->SR = 0;
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return 0xffff;
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}
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}
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// return sample (this also clears EOC flag)
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return ADC1->DR;
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}
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/*
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capture VSERVO in mV
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*/
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uint16_t adc_sample_vservo(void)
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{
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const uint32_t channel = ADC_SQR3_SQ1_N(ADC_CHANNEL_IN4);
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return adc_sample_channel(channel);
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}
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/*
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capture VRSSI in mV
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*/
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uint16_t adc_sample_vrssi(void)
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{
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const uint32_t channel = ADC_SQR3_SQ1_N(ADC_CHANNEL_IN5);
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return adc_sample_channel(channel);
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}
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