/****************************************************************************** * The MIT License * * Copyright (c) 2010 Perry Hung. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. *****************************************************************************/ /** * @file adc.c * * @brief Analog to digital converter routines * * IMPORTANT: maximum external impedance must be below 0.4kOhms for 1.5 * sample conversion time. * * At 55.5 cycles/sample, the external input impedance < 50kOhms. * * See STM32 manual RM0008 for how to calculate this. */ #include "libmaple.h" #include "rcc.h" #include "adc.h" adc_dev adc1 = { .regs = ADC1_BASE, .clk_id = RCC_ADC1 }; const adc_dev *ADC1 = &adc1; adc_dev adc2 = { .regs = ADC2_BASE, .clk_id = RCC_ADC2 }; const adc_dev *ADC2 = &adc2; #ifdef STM32_HIGH_DENSITY adc_dev adc3 = { .regs = ADC3_BASE, .clk_id = RCC_ADC3 }; const adc_dev *ADC3 = &adc3; #endif /** * @brief Initialize an ADC peripheral. * * Initializes the RCC clock line for the given peripheral, using ADC * prescaler RCC_ADCPRE_PCLK_DIV_6. Resets ADC device registers. * * @param dev ADC peripheral to initialize */ void adc_init(const adc_dev *dev) { rcc_set_prescaler(RCC_PRESCALER_ADC, RCC_ADCPRE_PCLK_DIV_6); rcc_clk_enable(dev->clk_id); rcc_reset_dev(dev->clk_id); } /** * @brief Set external event select for regular group * @param dev ADC device * @param event Event used to trigger the start of conversion. * @see adc_extsel_event */ void adc_set_extsel(const adc_dev *dev, adc_extsel_event event) { uint32 cr2 = dev->regs->CR2; cr2 &= ~ADC_CR2_EXTSEL; cr2 |= event; dev->regs->CR2 = cr2; } /** * @brief Call a function on all ADC devices. * @param fn Function to call on each ADC device. */ void adc_foreach(void (*fn)(const adc_dev*)) { fn(ADC1); fn(ADC2); #ifdef STM32_HIGH_DENSITY fn(ADC3); #endif } /** * @brief Turn the given sample rate into values for ADC_SMPRx. Don't * call this during conversion. * @param dev adc device * @param smp_rate sample rate to set * @see adc_smp_rate */ void adc_set_sample_rate(const adc_dev *dev, adc_smp_rate smp_rate) { uint32 adc_smpr1_val = 0, adc_smpr2_val = 0; int i; for (i = 0; i < 10; i++) { if (i < 8) { /* ADC_SMPR1 determines sample time for channels [10,17] */ adc_smpr1_val |= smp_rate << (i * 3); } /* ADC_SMPR2 determines sample time for channels [0,9] */ adc_smpr2_val |= smp_rate << (i * 3); } dev->regs->SMPR1 = adc_smpr1_val; dev->regs->SMPR2 = adc_smpr2_val; } /** * @brief Calibrate an ADC peripheral * @param dev adc device */ void adc_calibrate(const adc_dev *dev) { __io uint32 *rstcal_bit = bb_perip(&(dev->regs->CR2), 3); __io uint32 *cal_bit = bb_perip(&(dev->regs->CR2), 2); *rstcal_bit = 1; while (*rstcal_bit) ; *cal_bit = 1; while (*cal_bit) ; } /** * @brief Perform a single synchronous software triggered conversion on a * channel. * @param dev ADC device to use for reading. * @param channel channel to convert * @return conversion result */ uint16 adc_read(const adc_dev *dev, uint8 channel) { adc_reg_map *regs = dev->regs; adc_set_reg_seqlen(dev, 1); regs->SQR3 = channel; regs->CR2 |= ADC_CR2_SWSTART; while(!(regs->SR & ADC_SR_EOC)) ; return (uint16)(regs->DR & ADC_DR_DATA); }