ad7124_support.c

00001 /*!
00002  *****************************************************************************
00003   @file:  ad7124_support.c
00004 
00005   @brief: Provides useful support functions for the AD7124 NoOS driver
00006 
00007   @details:
00008  -----------------------------------------------------------------------------
00009  Copyright (c) 2019, 2020 Analog Devices, Inc.
00010  All rights reserved.
00011 
00012  This software is proprietary to Analog Devices, Inc. and its licensors.
00013  By using this software you agree to the terms of the associated
00014  Analog Devices Software License Agreement.
00015 *****************************************************************************/
00016 
00017 #include <stdbool.h>
00018 #include "ad7124_support.h"
00019 
00020 // Public Functions
00021 /*
00022  * @brief helper function get the setup setting for an ADC channel
00023  *
00024  * @param dev The device structure.
00025  *
00026  * @param channel ADC channel to get Setup for.
00027  *
00028  * @return value of setup field in channel configuration.
00029  */
00030 uint8_t ad7124_get_channel_setup(struct ad7124_dev *dev, uint8_t channel)
00031 {
00032     return (dev->regs[AD7124_Channel_0 + channel].value >> 12) & 0x7;
00033 }
00034 
00035 
00036 /*
00037  * @brief helper function get the PGA setting for an ADC channel
00038  *
00039  * @param dev The device structure.
00040  *
00041  * @param channel ADC channel to get Setup for.
00042  *
00043  * @return value of PGA field in the setup for an ADC channel.
00044  */
00045 uint8_t ad7124_get_channel_pga(struct ad7124_dev *dev, uint8_t channel)
00046 {
00047     uint8_t setup = ad7124_get_channel_setup(dev, channel);
00048 
00049     return (dev->regs[AD7124_Config_0 + setup].value) & 0x07;
00050 }
00051 
00052 
00053 /*
00054  * @brief helper function get the bipolar setting for an ADC channel
00055  *
00056  * @param dev The device structure.
00057  *
00058  * @param channel ADC channel to get bipolar mode for.
00059  *
00060  * @return value of bipolar field in the setup for an ADC channel.
00061  */
00062 bool ad7124_get_channel_bipolar(struct ad7124_dev *dev, uint8_t channel)
00063 {
00064     uint8_t setup = ad7124_get_channel_setup(dev, channel);
00065 
00066     return ((dev->regs[AD7124_Config_0 + setup].value >> 11) & 0x1) ? true : false;
00067 }
00068 
00069 
00070 /*
00071  * @brief converts ADC sample value to voltage based on gain setting
00072  *
00073  * @param dev The device structure.
00074  *
00075  * @param channel ADC channel to get Setup for.
00076  *
00077  * @param sample Raw ADC sample
00078  *
00079  * @return Sample ADC value converted to voltage.
00080  *
00081  * @note The conversion equation is implemented for simplicity,
00082  *       not for accuracy or performance
00083  *
00084  */
00085 float ad7124_convert_sample_to_voltage(struct ad7124_dev *dev, uint8_t channel,
00086                        uint32_t sample)
00087 {
00088     bool isBipolar = ad7124_get_channel_bipolar(dev, channel);
00089     uint8_t channelPGA = ad7124_get_channel_pga(dev, channel);
00090 
00091     float convertedValue;
00092 
00093     if (isBipolar) {
00094         convertedValue = ( ((float)sample / (1 << (AD7124_ADC_N_BITS -1))) -1 ) * \
00095                  (AD7124_REF_VOLTAGE / AD7124_PGA_GAIN(channelPGA));
00096     } else {
00097         convertedValue = ((float)sample * AD7124_REF_VOLTAGE)/(AD7124_PGA_GAIN(
00098                      channelPGA) * \
00099                  (1 << AD7124_ADC_N_BITS));
00100     }
00101 
00102     return (convertedValue);
00103 }