130 lines
4.1 KiB
C
130 lines
4.1 KiB
C
#ifndef __ADCMEAS_H__
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#define __ADCMEAS_H__
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#include <stdbool.h>
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#include <stdint.h>
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#include <stm32f4xx.h>
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/**
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* @brief Moving average filter coefficient for PT1000 measurement
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*/
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#define ADC_PT1000_FILTER_WEIGHT 0.005f
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/**
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* @brief ADC channel number of PT1000 sensor input
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*/
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#define ADC_PT1000_CHANNEL 2U
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#define ADC_PT1000_PORT GPIOA
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#define ADC_PT1000_PORT_RCC_MASK RCC_AHB1ENR_GPIOAEN
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#define ADC_PT1000_PIN 2U
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#define ADC_FILTER_STARTUP_CYCLES 800U
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#define ADC_PT1000_SAMPLE_CNT_DELAY 1000U
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#define ADC_PT1000_DMA_AVG_SAMPLES 6U
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/**
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* @brief Lower value for valid input range for PT1000 measurement
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*
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* If the input of the PT1000 sensor is below this value, an error is thrown. This is used to disable the temperature control loop
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*/
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#define ADC_PT1000_LOWER_WATCHDOG 200U
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/**
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* @brief Upper value for valid input range for PT1000 measurement
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*
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* If the input of the PT1000 sensor is above this value, an error is thrown. This is used to disable the temperature control loop
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*/
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#define ADC_PT1000_UPPER_WATCHDOG 4000U
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enum adc_pt1000_error {ADC_PT1000_NO_ERR= 0, ADC_PT1000_WATCHDOG_ERROR=(1UL<<0), ADC_PT1000_OVERFLOW=(1UL<<1)};
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/**
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* @brief This function sets up the ADC measurement fo the external PT1000 temperature sensor
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*
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* Used peripherals:
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* - Timer 2 for sampling control
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* - ADC1
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*
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* The filter weight \f$\alpha\f$ is configured for @ref ADC_PT1000_FILTER_WEIGHT
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*
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*/
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void adc_pt1000_setup_meas();
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/**
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* @brief Set moving average filter parameters
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*
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* The sampled resistance value is filtered with an exponential average filter
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* specified by following difference equation:
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*
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* \f$ y[n] = (1-\alpha)y[n-1] + \alpha x[n] \f$
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*
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* @param alpha
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*/
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void adc_pt1000_set_moving_average_filter_param(float alpha);
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/**
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* @brief Set the calibration data for the PT1000 measurement
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*
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* The resulting resistance reading is
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* \f$R_{corrected} = (1 + \sigma) R_{raw} + O\f$
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*
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* @param offset Offset \f$O\f$
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* @param sensitivity_deviation Sensitivity Deviation \f$\sigma\f$ after offset correction
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*/
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void adc_pt1000_set_resistance_calibration(float offset, float sensitivity_deviation, bool active);
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/**
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* @brief Get the state and values of the resistance calibration
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* @param offset Offset
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* @param sensitivity_deviation Sensitivity deviation
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* @param active Active state of the correction
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*/
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void adc_pt1000_get_resistance_calibration(float *offset, float *sensitivity_deviation, bool *active);
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/**
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* @brief Get the current reistance value
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*
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* If the reistance calibration is enabled, this function applies the calculations of the raw reistance reading and
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* returns the corrected value.
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*
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* If an ADC error is set, the status is negative. The status is 2 during the first measurements with a given filter setting. Technically, the resistance value is
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* correct but the filter is not stable yet.
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* Use adc_pt1000_check_error to check the error and reinitialize the ADC.
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*
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*
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* @param[out] resistance Resistance output in Ohms
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* @return Status
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*/
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int adc_pt1000_get_current_resistance(float *resistance);
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/**
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* @brief Stream the raw ADC data to an array in memory.
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*
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* Streaming is done using DMA2 Stream0.
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* This function is used for gathering fullspeed sampling data for external interfaces or calibration
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*
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* @param adc_array Array to stream data to
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* @param length Amount of data points to be measured
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* @param flag_to_set This flag is set to 1 once the data has been measured and is transferred. A negative value indicates an error
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* @return 0 if measurement could be started
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*/
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int adc_pt1000_stream_raw_value_to_memory(float *adc_array, uint32_t length, volatile uint8_t *flag_to_set);
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void adc_pt1000_convert_raw_value_array_to_resistance(float *resistance_dest, float *raw_source, uint32_t count);
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/**
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* @brief Check if the ADC measurement experienced any kind of error (DMA, Analog Watchdog, etc...)
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*
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* In case of an error, it may be necessary to call adc_pt1000_setup_meas() again in order to recover from the error
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*/
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enum adc_pt1000_error adc_pt1000_check_error();
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void adc_pt1000_clear_error();
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void adc_pt1000_disable();
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#endif // __ADCMEAS_H__
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