Janani Sunil / platform_drivers

Forked repo of Platform Drivers- Analog Devices

adc_data_capture.c@18:5ae03a197e59, 2021-08-02 (annotated)

Committer:
mahphalke
Date:
Mon Aug 02 16:03:08 2021 +0530
Revision:
18:5ae03a197e59
Parent:
17:af1f2416dd26 
Modified the ADC data capture module to remove dependancy on type of ADC and it's specific operations

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mahphalke 17:af1f2416dd26 1 /***************************************************************************//**
mahphalke 17:af1f2416dd26 2 * @file adc_data_capture.c
mahphalke 17:af1f2416dd26 3 * @brief ADC common data capture interface for IIO based applications
mahphalke 17:af1f2416dd26 4 * @details This module handles the ADC data capturing for IIO client
mahphalke 17:af1f2416dd26 5 ********************************************************************************
mahphalke 17:af1f2416dd26 6 * Copyright (c) 2021 Analog Devices, Inc.
mahphalke 17:af1f2416dd26 7 * All rights reserved.
mahphalke 17:af1f2416dd26 8 *
mahphalke 17:af1f2416dd26 9 * This software is proprietary to Analog Devices, Inc. and its licensors.
mahphalke 17:af1f2416dd26 10 * By using this software you agree to the terms of the associated
mahphalke 17:af1f2416dd26 11 * Analog Devices Software License Agreement.
mahphalke 17:af1f2416dd26 12 *******************************************************************************/
mahphalke 17:af1f2416dd26 13
mahphalke 17:af1f2416dd26 14 /******************************************************************************/
mahphalke 17:af1f2416dd26 15 /***************************** Include Files **********************************/
mahphalke 17:af1f2416dd26 16 /******************************************************************************/
mahphalke 17:af1f2416dd26 17
mahphalke 17:af1f2416dd26 18 #include <stdint.h>
mahphalke 17:af1f2416dd26 19 #include <stdbool.h>
mahphalke 17:af1f2416dd26 20 #include <string.h>
mahphalke 17:af1f2416dd26 21
mahphalke 17:af1f2416dd26 22 #include "adc_data_capture.h"
mahphalke 17:af1f2416dd26 23 #include "error.h"
mahphalke 17:af1f2416dd26 24
mahphalke 17:af1f2416dd26 25 /******************************************************************************/
mahphalke 17:af1f2416dd26 26 /********************** Macros and Constants Definition ***********************/
mahphalke 17:af1f2416dd26 27 /******************************************************************************/
mahphalke 17:af1f2416dd26 28
mahphalke 18:5ae03a197e59 29 /* Max available channels for continuous data capture. Actual number of channels
mahphalke 18:5ae03a197e59 30 * to be captured are supplied from an application */
mahphalke 18:5ae03a197e59 31 #define MAX_AVAILABLE_CHANNELS (16)
mahphalke 17:af1f2416dd26 32
mahphalke 18:5ae03a197e59 33 /* Max size of the acquisition buffer (in terms of bytes) */
mahphalke 18:5ae03a197e59 34 #define DATA_BUFFER_SIZE (32768) // 32Kbytes
mahphalke 17:af1f2416dd26 35
mahphalke 17:af1f2416dd26 36 /* Timeout count to avoid stuck into potential infinite loop while checking
mahphalke 17:af1f2416dd26 37 * for new data into an acquisition buffer. The actual timeout factor is determined
mahphalke 18:5ae03a197e59 38 * through 'sampling_frequency' attribute of IIO app, but this period here makes sure
mahphalke 18:5ae03a197e59 39 * we are not stuck into a forever loop in case data capture is interrupted
mahphalke 18:5ae03a197e59 40 * or failed in between.
mahphalke 18:5ae03a197e59 41 * Note: This timeout factor is dependent upon the MCU clock frequency. Below timeout
mahphalke 18:5ae03a197e59 42 * is tested for SDP-K1 platform @180Mhz default core clock */
mahphalke 17:af1f2416dd26 43 #define BUF_READ_TIMEOUT (100000000)
mahphalke 17:af1f2416dd26 44
mahphalke 17:af1f2416dd26 45 /******************************************************************************/
mahphalke 17:af1f2416dd26 46 /********************** Variables and User Defined Data Types *****************/
mahphalke 17:af1f2416dd26 47 /******************************************************************************/
mahphalke 17:af1f2416dd26 48
mahphalke 18:5ae03a197e59 49 /* Extern declaration for device specific data capture operations structure
mahphalke 18:5ae03a197e59 50 * (actual definition should be present in an application) */
mahphalke 17:af1f2416dd26 51 extern struct data_capture_ops data_capture_ops;
mahphalke 17:af1f2416dd26 52
mahphalke 17:af1f2416dd26 53 /*
mahphalke 17:af1f2416dd26 54 *@enum acq_buffer_state_e
mahphalke 17:af1f2416dd26 55 *@details Enum holding the data acquisition buffer states
mahphalke 17:af1f2416dd26 56 **/
mahphalke 17:af1f2416dd26 57 typedef enum {
mahphalke 17:af1f2416dd26 58 BUF_AVAILABLE,
mahphalke 17:af1f2416dd26 59 BUF_EMPTY,
mahphalke 17:af1f2416dd26 60 BUF_FULL
mahphalke 17:af1f2416dd26 61 } acq_buffer_state_e;
mahphalke 17:af1f2416dd26 62
mahphalke 17:af1f2416dd26 63 /*
mahphalke 17:af1f2416dd26 64 *@struct acq_buf_t
mahphalke 17:af1f2416dd26 65 *@details Structure holding the data acquisition buffer parameters
mahphalke 17:af1f2416dd26 66 **/
mahphalke 17:af1f2416dd26 67 typedef struct {
mahphalke 18:5ae03a197e59 68 acq_buffer_state_e state; // Buffer state
mahphalke 18:5ae03a197e59 69 bool refill_buffer; // Flag to start refilling acquisition buffer
mahphalke 18:5ae03a197e59 70 uint32_t rd_indx; // Buffer read index (incremented per sample transmit)
mahphalke 18:5ae03a197e59 71 uint32_t wr_indx; // Buffer write index (incremented per sample read)
mahphalke 18:5ae03a197e59 72 uint8_t sample_size; // ADC sample/raw data size received from application
mahphalke 18:5ae03a197e59 73 uint8_t chn_indx; // ADC channel index into acquisition buffer
mahphalke 18:5ae03a197e59 74 uint8_t active_chn[MAX_AVAILABLE_CHANNELS]; // Active channel number sequence
mahphalke 18:5ae03a197e59 75 uint8_t data[DATA_BUFFER_SIZE]; // buffer data (adc raw values)
mahphalke 18:5ae03a197e59 76 uint8_t *pdata; // Pointer to data buffer
mahphalke 17:af1f2416dd26 77 } acq_buf_t;
mahphalke 17:af1f2416dd26 78
mahphalke 17:af1f2416dd26 79 /* ADC data acquisition buffers */
mahphalke 17:af1f2416dd26 80 static volatile acq_buf_t acq_buffer;
mahphalke 17:af1f2416dd26 81
mahphalke 17:af1f2416dd26 82 /* Flag to indicate data capture status */
mahphalke 17:af1f2416dd26 83 static volatile bool start_adc_data_capture = false;
mahphalke 17:af1f2416dd26 84
mahphalke 17:af1f2416dd26 85 /* Number of active channels in any data buffer read request */
mahphalke 17:af1f2416dd26 86 static volatile uint8_t num_of_active_channels = 0;
mahphalke 17:af1f2416dd26 87
mahphalke 17:af1f2416dd26 88 /* Count to track number of actual samples requested by IIO client */
mahphalke 17:af1f2416dd26 89 static volatile uint16_t num_of_requested_samples = 0;
mahphalke 17:af1f2416dd26 90
mahphalke 18:5ae03a197e59 91 /* Channel alignment offset */
mahphalke 18:5ae03a197e59 92 static volatile uint8_t chn_alignment_offset = 0;
mahphalke 18:5ae03a197e59 93
mahphalke 17:af1f2416dd26 94 /* Actual or max available size of acquisition buffer */
mahphalke 17:af1f2416dd26 95 static volatile uint16_t max_available_buffer_size = 0;
mahphalke 17:af1f2416dd26 96
mahphalke 17:af1f2416dd26 97 /******************************************************************************/
mahphalke 17:af1f2416dd26 98 /************************ Functions Declarations ******************************/
mahphalke 17:af1f2416dd26 99 /******************************************************************************/
mahphalke 17:af1f2416dd26 100
mahphalke 17:af1f2416dd26 101 /******************************************************************************/
mahphalke 17:af1f2416dd26 102 /************************ Functions Definitions *******************************/
mahphalke 17:af1f2416dd26 103 /******************************************************************************/
mahphalke 17:af1f2416dd26 104
mahphalke 17:af1f2416dd26 105 /*!
mahphalke 18:5ae03a197e59 106 * @brief Function to read the single ADC sample (raw data) for input channel
mahphalke 17:af1f2416dd26 107 * @param input_chn[in] - Input channel to sample and read data for
mahphalke 17:af1f2416dd26 108 * @param raw_data[in, out]- ADC raw data
mahphalke 17:af1f2416dd26 109 * @return SUCCESS in case of success, FAILURE otherwise
mahphalke 17:af1f2416dd26 110 */
mahphalke 18:5ae03a197e59 111 int32_t read_single_sample(uint8_t input_chn, uint32_t *raw_data)
mahphalke 17:af1f2416dd26 112 {
mahphalke 17:af1f2416dd26 113 uint32_t read_adc_data = 0;
mahphalke 17:af1f2416dd26 114 int32_t status = SUCCESS;
mahphalke 17:af1f2416dd26 115
mahphalke 17:af1f2416dd26 116 do {
mahphalke 18:5ae03a197e59 117 /* Perform operations required before single sample conversion read */
mahphalke 18:5ae03a197e59 118 if (data_capture_ops.single_sample_read_start_ops) {
mahphalke 18:5ae03a197e59 119 if (data_capture_ops.single_sample_read_start_ops(input_chn) != SUCCESS) {
mahphalke 17:af1f2416dd26 120 status = FAILURE;
mahphalke 17:af1f2416dd26 121 break;
mahphalke 17:af1f2416dd26 122 }
mahphalke 17:af1f2416dd26 123 }
mahphalke 17:af1f2416dd26 124
mahphalke 18:5ae03a197e59 125 /* Perform ADC conversion and read the converted sample after EOC */
mahphalke 18:5ae03a197e59 126 if (data_capture_ops.perform_conv_and_read_sample(&read_adc_data, input_chn) !=
mahphalke 17:af1f2416dd26 127 SUCCESS) {
mahphalke 17:af1f2416dd26 128 status = FAILURE;
mahphalke 17:af1f2416dd26 129 break;
mahphalke 17:af1f2416dd26 130 }
mahphalke 17:af1f2416dd26 131 } while (0);
mahphalke 17:af1f2416dd26 132
mahphalke 18:5ae03a197e59 133 /* Perform operations required post single sample conversion read */
mahphalke 18:5ae03a197e59 134 if (data_capture_ops.single_sample_read_stop_ops) {
mahphalke 18:5ae03a197e59 135 if (data_capture_ops.single_sample_read_stop_ops(input_chn) != SUCCESS) {
mahphalke 18:5ae03a197e59 136 status = FAILURE;
mahphalke 18:5ae03a197e59 137 }
mahphalke 17:af1f2416dd26 138 }
mahphalke 17:af1f2416dd26 139
mahphalke 17:af1f2416dd26 140 *raw_data = read_adc_data;
mahphalke 17:af1f2416dd26 141 return status;
mahphalke 17:af1f2416dd26 142 }
mahphalke 17:af1f2416dd26 143
mahphalke 17:af1f2416dd26 144
mahphalke 17:af1f2416dd26 145 /*!
mahphalke 18:5ae03a197e59 146 * @brief Function to store the number of actul requested ADC samples from IIO client
mahphalke 17:af1f2416dd26 147 * @param bytes[in] - Number of bytes corresponding to requested samples
mahphalke 17:af1f2416dd26 148 * @param sample_size_in_bytes[in] - Size of each sample in bytes (eqv to ADC resolution)
mahphalke 17:af1f2416dd26 149 * @return none
mahphalke 18:5ae03a197e59 150 * @note The information about sample and buffer size is required for continuous
mahphalke 18:5ae03a197e59 151 * data acquisition
mahphalke 17:af1f2416dd26 152 */
mahphalke 17:af1f2416dd26 153 void store_requested_samples_count(size_t bytes, uint8_t sample_size_in_bytes)
mahphalke 17:af1f2416dd26 154 {
mahphalke 17:af1f2416dd26 155 /* This gets the number of samples requested by IIO client for all active channels */
mahphalke 17:af1f2416dd26 156 num_of_requested_samples = bytes / sample_size_in_bytes;
mahphalke 17:af1f2416dd26 157
mahphalke 18:5ae03a197e59 158 /* Store the ADC sample size */
mahphalke 18:5ae03a197e59 159 acq_buffer.sample_size = sample_size_in_bytes;
mahphalke 18:5ae03a197e59 160
mahphalke 17:af1f2416dd26 161 /* Get the actual available size of buffer by aligning with number of requested samples.
mahphalke 18:5ae03a197e59 162 * e.g. if requested samples are 400 and sample size is 2 bytes, the max available
mahphalke 18:5ae03a197e59 163 * size of buffer is: available size = ((32768 / 2) / 400) * 400 = 40 * 400 = 16000.
mahphalke 17:af1f2416dd26 164 * The max samples to be requested should always be less than half the max size of buffer
mahphalke 18:5ae03a197e59 165 * (in this case: (32768/2) / 2 = 8192).
mahphalke 17:af1f2416dd26 166 * */
mahphalke 18:5ae03a197e59 167 max_available_buffer_size = ((DATA_BUFFER_SIZE / sample_size_in_bytes) /
mahphalke 18:5ae03a197e59 168 num_of_requested_samples) * num_of_requested_samples;
mahphalke 17:af1f2416dd26 169 }
mahphalke 17:af1f2416dd26 170
mahphalke 17:af1f2416dd26 171
mahphalke 17:af1f2416dd26 172 /*!
mahphalke 18:5ae03a197e59 173 * @brief Function to read acquired samples into buffer without IIO request timeout
mahphalke 17:af1f2416dd26 174 * @param input_buffer[in] - Input data acquisition buffer
mahphalke 17:af1f2416dd26 175 * @param output_buffer[in, out] - Output data buffer
mahphalke 17:af1f2416dd26 176 * @param samples_to_read[in] - Number of samples to read
mahphalke 17:af1f2416dd26 177 * @param sample_size_in_bytes[in] - Size of each sample in bytes (eqv to ADC resolution)
mahphalke 17:af1f2416dd26 178 * @return none
mahphalke 17:af1f2416dd26 179 */
mahphalke 18:5ae03a197e59 180 static void read_acquired_samples(char *output_buffer,
mahphalke 18:5ae03a197e59 181 size_t samples_to_read,
mahphalke 18:5ae03a197e59 182 uint8_t sample_size_in_bytes)
mahphalke 17:af1f2416dd26 183 {
mahphalke 18:5ae03a197e59 184 int32_t buff_rd_wr_indx_offset; // Offset b/w buffer read and write indexes
mahphalke 18:5ae03a197e59 185 uint32_t timeout = BUF_READ_TIMEOUT; // Buffer new data read timeout count
mahphalke 17:af1f2416dd26 186 size_t bytes = samples_to_read * sample_size_in_bytes;
mahphalke 17:af1f2416dd26 187
mahphalke 17:af1f2416dd26 188 /* Copy the bytes into buffer provided there is enough offset b/w read and write counts.
mahphalke 17:af1f2416dd26 189 * If there is overlap b/w read and write indexes (read is faster than write), empty buffer
mahphalke 17:af1f2416dd26 190 * should be returned to IIO client to avoid IIO request timeout */
mahphalke 17:af1f2416dd26 191 do {
mahphalke 17:af1f2416dd26 192 buff_rd_wr_indx_offset = (acq_buffer.wr_indx - acq_buffer.rd_indx);
mahphalke 17:af1f2416dd26 193 timeout--;
mahphalke 17:af1f2416dd26 194 } while (((buff_rd_wr_indx_offset < (int32_t)(samples_to_read))
mahphalke 17:af1f2416dd26 195 || (acq_buffer.wr_indx < acq_buffer.rd_indx)) && (timeout > 0)
mahphalke 17:af1f2416dd26 196 && start_adc_data_capture);
mahphalke 17:af1f2416dd26 197
mahphalke 17:af1f2416dd26 198 if ((timeout == 0) || (acq_buffer.wr_indx <= 0)) {
mahphalke 17:af1f2416dd26 199 /* This returns the empty buffer */
mahphalke 17:af1f2416dd26 200 return;
mahphalke 17:af1f2416dd26 201 }
mahphalke 17:af1f2416dd26 202
mahphalke 17:af1f2416dd26 203 memcpy(output_buffer,
mahphalke 18:5ae03a197e59 204 (void const *)&acq_buffer.data[acq_buffer.rd_indx * sample_size_in_bytes],
mahphalke 17:af1f2416dd26 205 bytes);
mahphalke 17:af1f2416dd26 206 acq_buffer.rd_indx += samples_to_read;
mahphalke 17:af1f2416dd26 207 }
mahphalke 17:af1f2416dd26 208
mahphalke 17:af1f2416dd26 209
mahphalke 17:af1f2416dd26 210 /*!
mahphalke 17:af1f2416dd26 211 * @brief Function to read and align the ADC buffered raw data
mahphalke 17:af1f2416dd26 212 * @param device[in]- Device instance
mahphalke 17:af1f2416dd26 213 * @param pbuf[out] - Buffer to load ADC raw data
mahphalke 17:af1f2416dd26 214 * @param bytes[in] - Number of bytes to be read
mahphalke 17:af1f2416dd26 215 * @param active_chns_mask[in] - Active channels mask
mahphalke 17:af1f2416dd26 216 * @return Number of bytes read
mahphalke 17:af1f2416dd26 217 */
mahphalke 18:5ae03a197e59 218 size_t read_buffered_data(char *pbuf,
mahphalke 18:5ae03a197e59 219 size_t bytes,
mahphalke 18:5ae03a197e59 220 size_t offset,
mahphalke 18:5ae03a197e59 221 uint32_t active_chns_mask,
mahphalke 18:5ae03a197e59 222 uint8_t sample_size_in_bytes)
mahphalke 17:af1f2416dd26 223 {
mahphalke 17:af1f2416dd26 224 size_t samples_to_read = bytes /
mahphalke 18:5ae03a197e59 225 sample_size_in_bytes; // Bytes to sample conversion
mahphalke 17:af1f2416dd26 226
mahphalke 17:af1f2416dd26 227 /* Make sure requested samples size is less than ADC buffer size. Return constant
mahphalke 17:af1f2416dd26 228 * value to avoid IIO client getting timed-out */
mahphalke 18:5ae03a197e59 229 if(num_of_requested_samples >= max_available_buffer_size) {
mahphalke 17:af1f2416dd26 230 memset(pbuf, 1, bytes);
mahphalke 17:af1f2416dd26 231 return bytes;
mahphalke 17:af1f2416dd26 232 }
mahphalke 17:af1f2416dd26 233
mahphalke 18:5ae03a197e59 234 /* Increment read counter to point to next acquired data of 1st active channel */
mahphalke 18:5ae03a197e59 235 if ((offset == 0) && (acq_buffer.rd_indx > 0)) {
mahphalke 18:5ae03a197e59 236 acq_buffer.rd_indx += chn_alignment_offset;
mahphalke 18:5ae03a197e59 237 }
mahphalke 17:af1f2416dd26 238
mahphalke 18:5ae03a197e59 239 read_acquired_samples(pbuf, samples_to_read, sample_size_in_bytes);
mahphalke 18:5ae03a197e59 240
mahphalke 18:5ae03a197e59 241 /* Make buffer available again once it is read/transmited completely */
mahphalke 17:af1f2416dd26 242 if (acq_buffer.rd_indx >= max_available_buffer_size) {
mahphalke 17:af1f2416dd26 243 acq_buffer.rd_indx = 0;
mahphalke 17:af1f2416dd26 244 acq_buffer.wr_indx = 0;
mahphalke 18:5ae03a197e59 245 acq_buffer.pdata = acq_buffer.data;
mahphalke 17:af1f2416dd26 246 acq_buffer.state = BUF_AVAILABLE;
mahphalke 18:5ae03a197e59 247 acq_buffer.refill_buffer = true;
mahphalke 17:af1f2416dd26 248 }
mahphalke 17:af1f2416dd26 249
mahphalke 17:af1f2416dd26 250 return bytes;
mahphalke 17:af1f2416dd26 251 }
mahphalke 17:af1f2416dd26 252
mahphalke 17:af1f2416dd26 253
mahphalke 17:af1f2416dd26 254 /*!
mahphalke 17:af1f2416dd26 255 * @brief This is an ISR (Interrupt Service Routine) to monitor end of conversion event.
mahphalke 17:af1f2416dd26 256 * @param *ctx[in] - Callback context (unused)
mahphalke 17:af1f2416dd26 257 * @param event[in] - Callback event (unused)
mahphalke 17:af1f2416dd26 258 * @param extra[in] - Callback extra (unused)
mahphalke 17:af1f2416dd26 259 * @return none
mahphalke 17:af1f2416dd26 260 * @details This is an Interrupt callback function/ISR invoked in synchronous/asynchronous
mahphalke 17:af1f2416dd26 261 * manner depending upon the application implementation. The conversion results
mahphalke 17:af1f2416dd26 262 * are read into acquisition buffer and control continue to sample next channel.
mahphalke 17:af1f2416dd26 263 * This continues until conversion is stopped (through IIO client command)
mahphalke 18:5ae03a197e59 264 * @note This function also handles the logic to align the first channel data after
mahphalke 17:af1f2416dd26 265 * every 'n' sample transmission. This is required to visualize data properly
mahphalke 18:5ae03a197e59 266 * on IIO client application.
mahphalke 17:af1f2416dd26 267 */
mahphalke 17:af1f2416dd26 268 void data_capture_callback(void *ctx, uint32_t event, void *extra)
mahphalke 17:af1f2416dd26 269 {
mahphalke 17:af1f2416dd26 270 uint32_t adc_sample;
mahphalke 17:af1f2416dd26 271
mahphalke 17:af1f2416dd26 272 if (start_adc_data_capture == true) {
mahphalke 18:5ae03a197e59 273 /* Read the sample(s) for channel(s) which has/have been sampled recently and
mahphalke 18:5ae03a197e59 274 * get the number of samples read count */
mahphalke 18:5ae03a197e59 275 if (data_capture_ops.read_converted_sample(&adc_sample,
mahphalke 18:5ae03a197e59 276 acq_buffer.active_chn[acq_buffer.chn_indx]) != FAILURE) {
mahphalke 18:5ae03a197e59 277 do {
mahphalke 18:5ae03a197e59 278 if (acq_buffer.state == BUF_AVAILABLE) {
mahphalke 18:5ae03a197e59 279 if (acq_buffer.refill_buffer) {
mahphalke 18:5ae03a197e59 280 /* Buffer refilling must start with first active channel data
mahphalke 18:5ae03a197e59 281 * for IIO client to synchronize the buffered data */
mahphalke 18:5ae03a197e59 282 if (acq_buffer.chn_indx != 0) {
mahphalke 18:5ae03a197e59 283 break;
mahphalke 18:5ae03a197e59 284 }
mahphalke 18:5ae03a197e59 285 acq_buffer.refill_buffer = false;
mahphalke 18:5ae03a197e59 286 }
mahphalke 17:af1f2416dd26 287
mahphalke 18:5ae03a197e59 288 /* Copy adc samples into acquisition buffer to transport over
mahphalke 18:5ae03a197e59 289 * communication link */
mahphalke 18:5ae03a197e59 290 memcpy(acq_buffer.pdata, &adc_sample, acq_buffer.sample_size);
mahphalke 18:5ae03a197e59 291 acq_buffer.pdata += acq_buffer.sample_size;
mahphalke 17:af1f2416dd26 292
mahphalke 18:5ae03a197e59 293 /* Check for acquisition buffer full condition */
mahphalke 18:5ae03a197e59 294 acq_buffer.wr_indx++;
mahphalke 18:5ae03a197e59 295 if (acq_buffer.wr_indx >= max_available_buffer_size) {
mahphalke 18:5ae03a197e59 296 acq_buffer.state = BUF_FULL;
mahphalke 18:5ae03a197e59 297 }
mahphalke 17:af1f2416dd26 298 }
mahphalke 18:5ae03a197e59 299 } while (0);
mahphalke 17:af1f2416dd26 300
mahphalke 18:5ae03a197e59 301 /* Keep tracking channel index as it is needed to refill the buffer
mahphalke 18:5ae03a197e59 302 * starting with first channel data */
mahphalke 18:5ae03a197e59 303 acq_buffer.chn_indx++;
mahphalke 18:5ae03a197e59 304 if (acq_buffer.chn_indx >= num_of_active_channels) {
mahphalke 18:5ae03a197e59 305 acq_buffer.chn_indx = 0;
mahphalke 17:af1f2416dd26 306 }
mahphalke 18:5ae03a197e59 307 }
mahphalke 17:af1f2416dd26 308
mahphalke 17:af1f2416dd26 309 /* Trigger next continuous conversion (optional or device dependent) */
mahphalke 18:5ae03a197e59 310 if (data_capture_ops.trigger_next_conversion) {
mahphalke 18:5ae03a197e59 311 data_capture_ops.trigger_next_conversion();
mahphalke 17:af1f2416dd26 312 }
mahphalke 17:af1f2416dd26 313 }
mahphalke 17:af1f2416dd26 314 }
mahphalke 17:af1f2416dd26 315
mahphalke 17:af1f2416dd26 316
mahphalke 17:af1f2416dd26 317 /*!
mahphalke 17:af1f2416dd26 318 * @brief Reset the data capture specific variables
mahphalke 17:af1f2416dd26 319 * @return none
mahphalke 17:af1f2416dd26 320 */
mahphalke 17:af1f2416dd26 321 static void reset_data_capture(void)
mahphalke 17:af1f2416dd26 322 {
mahphalke 17:af1f2416dd26 323 /* Reset data capture flags */
mahphalke 17:af1f2416dd26 324 start_adc_data_capture = false;
mahphalke 17:af1f2416dd26 325 num_of_active_channels = 0;
mahphalke 17:af1f2416dd26 326
mahphalke 17:af1f2416dd26 327 /* Reset acquisition buffer states and clear old data */
mahphalke 17:af1f2416dd26 328 acq_buffer.state = BUF_EMPTY;
mahphalke 17:af1f2416dd26 329
mahphalke 17:af1f2416dd26 330 acq_buffer.wr_indx = 0;
mahphalke 17:af1f2416dd26 331 acq_buffer.rd_indx = 0;
mahphalke 18:5ae03a197e59 332 acq_buffer.chn_indx = 0;
mahphalke 18:5ae03a197e59 333 acq_buffer.refill_buffer = false;
mahphalke 18:5ae03a197e59 334 acq_buffer.pdata = acq_buffer.data;
mahphalke 17:af1f2416dd26 335 }
mahphalke 17:af1f2416dd26 336
mahphalke 17:af1f2416dd26 337
mahphalke 17:af1f2416dd26 338 /*!
mahphalke 17:af1f2416dd26 339 * @brief Function to trigger ADC conversion for new READBUFF
mahphalke 17:af1f2416dd26 340 * request from IIO client (for active channels)
mahphalke 17:af1f2416dd26 341 * @param ch_mask[in] - Channels to enable for data capturing
mahphalke 17:af1f2416dd26 342 * @param num_of_chns[in] - ADC channel count
mahphalke 17:af1f2416dd26 343 * @return none
mahphalke 17:af1f2416dd26 344 */
mahphalke 17:af1f2416dd26 345 void start_data_capture(uint32_t ch_mask, uint8_t num_of_chns)
mahphalke 17:af1f2416dd26 346 {
mahphalke 17:af1f2416dd26 347 uint32_t mask = 0x1;
mahphalke 18:5ae03a197e59 348 uint8_t index = 0;
mahphalke 17:af1f2416dd26 349
mahphalke 18:5ae03a197e59 350 /* Make sure requested samples size is less than max available buffer size */
mahphalke 17:af1f2416dd26 351 if (num_of_requested_samples >= max_available_buffer_size) {
mahphalke 17:af1f2416dd26 352 return;
mahphalke 17:af1f2416dd26 353 }
mahphalke 17:af1f2416dd26 354
mahphalke 18:5ae03a197e59 355 /* Reset data capture module specific flags and variables */
mahphalke 17:af1f2416dd26 356 reset_data_capture();
mahphalke 17:af1f2416dd26 357
mahphalke 18:5ae03a197e59 358 /* Count active channels based on channel mask set in the IIO client */
mahphalke 17:af1f2416dd26 359 for (uint8_t chn = 0; chn < num_of_chns; chn++) {
mahphalke 17:af1f2416dd26 360 if (ch_mask & mask) {
mahphalke 18:5ae03a197e59 361 acq_buffer.active_chn[index++] = chn;
mahphalke 17:af1f2416dd26 362 num_of_active_channels++;
mahphalke 17:af1f2416dd26 363 }
mahphalke 17:af1f2416dd26 364
mahphalke 17:af1f2416dd26 365 mask <<= 1;
mahphalke 17:af1f2416dd26 366 }
mahphalke 17:af1f2416dd26 367
mahphalke 18:5ae03a197e59 368 /* Note: As shown below, after nth sample read, next sample must be for the first
mahphalke 18:5ae03a197e59 369 * channel present in the list of enabled channels */
mahphalke 18:5ae03a197e59 370 /*+-----------------------+-------------------------+---------------------------+
mahphalke 18:5ae03a197e59 371 *| 0 | 1 | 2 | ------| n | 0 | 1 | 2 | --------| n | 0 | 1 | 2 |-----------| l |
mahphalke 18:5ae03a197e59 372 *+-^-------------------^-+-^---------------------^-+-^-----------------------^-+
mahphalke 18:5ae03a197e59 373 * | | | | | |
mahphalke 18:5ae03a197e59 374 * 1st chn data nth data 1st chn data nth data 1st chn data last data
mahphalke 18:5ae03a197e59 375 * n = number of requested samples. l = last data (channel unknown)
mahphalke 18:5ae03a197e59 376 * To achieve this, offset value is determined based on the requested samples count
mahphalke 18:5ae03a197e59 377 * and number of active channels. The read index is then incremented by offset value
mahphalke 18:5ae03a197e59 378 * to read the data for first enabled channel by mapping into acquisition buffer.
mahphalke 18:5ae03a197e59 379 **/
mahphalke 18:5ae03a197e59 380 if (num_of_requested_samples % num_of_active_channels) {
mahphalke 18:5ae03a197e59 381 chn_alignment_offset = (num_of_requested_samples - ((num_of_requested_samples /
mahphalke 18:5ae03a197e59 382 num_of_active_channels) * num_of_active_channels)) + 1;
mahphalke 18:5ae03a197e59 383 } else {
mahphalke 18:5ae03a197e59 384 chn_alignment_offset = 0;
mahphalke 18:5ae03a197e59 385 }
mahphalke 18:5ae03a197e59 386
mahphalke 18:5ae03a197e59 387 /* Make acquisition buffer available and start continuous conversion */
mahphalke 17:af1f2416dd26 388 acq_buffer.state = BUF_AVAILABLE;
mahphalke 18:5ae03a197e59 389 if (data_capture_ops.continuous_sample_read_start_ops) {
mahphalke 18:5ae03a197e59 390 if (data_capture_ops.continuous_sample_read_start_ops(ch_mask) != FAILURE) {
mahphalke 18:5ae03a197e59 391 start_adc_data_capture = true;
mahphalke 18:5ae03a197e59 392 }
mahphalke 18:5ae03a197e59 393 } else {
mahphalke 17:af1f2416dd26 394 start_adc_data_capture = true;
mahphalke 17:af1f2416dd26 395 }
mahphalke 17:af1f2416dd26 396 }
mahphalke 17:af1f2416dd26 397
mahphalke 17:af1f2416dd26 398
mahphalke 17:af1f2416dd26 399 /*!
mahphalke 17:af1f2416dd26 400 * @brief Function to stop ADC data capture
mahphalke 17:af1f2416dd26 401 * @return none
mahphalke 17:af1f2416dd26 402 */
mahphalke 17:af1f2416dd26 403 void stop_data_capture(void)
mahphalke 17:af1f2416dd26 404 {
mahphalke 17:af1f2416dd26 405 start_adc_data_capture = false;
mahphalke 17:af1f2416dd26 406
mahphalke 18:5ae03a197e59 407 /* Enable operations required post continuous sample read */
mahphalke 18:5ae03a197e59 408 if (data_capture_ops.continuous_sample_read_stop_ops) {
mahphalke 18:5ae03a197e59 409 data_capture_ops.continuous_sample_read_stop_ops();
mahphalke 17:af1f2416dd26 410 }
mahphalke 17:af1f2416dd26 411
mahphalke 18:5ae03a197e59 412 /* Reset data capture module specific flags and variables */
mahphalke 17:af1f2416dd26 413 reset_data_capture();
mahphalke 17:af1f2416dd26 414 }