Analog Devices / mbed-drivers

A collection of Analog Devices drivers for the mbed platform

For additional information check out the mbed page of the Analog Devices wiki: https://wiki.analog.com/resources/tools-software/mbed-drivers-all

libraries/AD7790/AD7790.cpp@24:dae7123d432a, 2016-05-18 (annotated)

Committer:
Adrian Suciu
Date:
Wed May 18 16:57:57 2016 +0300
Revision:
24:dae7123d432a
Improved compatibility with Linux systems

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Adrian Suciu 24:dae7123d432a 1 /**
Adrian Suciu 24:dae7123d432a 2 * @file AD7790.cpp
Adrian Suciu 24:dae7123d432a 3 * @brief Source file for AD7790 ADC
Adrian Suciu 24:dae7123d432a 4 * @author Analog Devices Inc.
Adrian Suciu 24:dae7123d432a 5 *
Adrian Suciu 24:dae7123d432a 6 * For support please go to:
Adrian Suciu 24:dae7123d432a 7 * Github: https://github.com/analogdevicesinc/mbed-adi
Adrian Suciu 24:dae7123d432a 8 * Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers
Adrian Suciu 24:dae7123d432a 9 * Product: http://www.analog.com/ad7790
Adrian Suciu 24:dae7123d432a 10 * More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all
Adrian Suciu 24:dae7123d432a 11
Adrian Suciu 24:dae7123d432a 12 ********************************************************************************
Adrian Suciu 24:dae7123d432a 13 * Copyright 2016(c) Analog Devices, Inc.
Adrian Suciu 24:dae7123d432a 14 *
Adrian Suciu 24:dae7123d432a 15 * All rights reserved.
Adrian Suciu 24:dae7123d432a 16 *
Adrian Suciu 24:dae7123d432a 17 * Redistribution and use in source and binary forms, with or without
Adrian Suciu 24:dae7123d432a 18 * modification, are permitted provided that the following conditions are met:
Adrian Suciu 24:dae7123d432a 19 * - Redistributions of source code must retain the above copyright
Adrian Suciu 24:dae7123d432a 20 * notice, this list of conditions and the following disclaimer.
Adrian Suciu 24:dae7123d432a 21 * - Redistributions in binary form must reproduce the above copyright
Adrian Suciu 24:dae7123d432a 22 * notice, this list of conditions and the following disclaimer in
Adrian Suciu 24:dae7123d432a 23 * the documentation and/or other materials provided with the
Adrian Suciu 24:dae7123d432a 24 * distribution.
Adrian Suciu 24:dae7123d432a 25 * - Neither the name of Analog Devices, Inc. nor the names of its
Adrian Suciu 24:dae7123d432a 26 * contributors may be used to endorse or promote products derived
Adrian Suciu 24:dae7123d432a 27 * from this software without specific prior written permission.
Adrian Suciu 24:dae7123d432a 28 * - The use of this software may or may not infringe the patent rights
Adrian Suciu 24:dae7123d432a 29 * of one or more patent holders. This license does not release you
Adrian Suciu 24:dae7123d432a 30 * from the requirement that you obtain separate licenses from these
Adrian Suciu 24:dae7123d432a 31 * patent holders to use this software.
Adrian Suciu 24:dae7123d432a 32 * - Use of the software either in source or binary form, must be run
Adrian Suciu 24:dae7123d432a 33 * on or directly connected to an Analog Devices Inc. component.
Adrian Suciu 24:dae7123d432a 34 *
Adrian Suciu 24:dae7123d432a 35 * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
Adrian Suciu 24:dae7123d432a 36 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
Adrian Suciu 24:dae7123d432a 37 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
Adrian Suciu 24:dae7123d432a 38 * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
Adrian Suciu 24:dae7123d432a 39 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
Adrian Suciu 24:dae7123d432a 40 * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
Adrian Suciu 24:dae7123d432a 41 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
Adrian Suciu 24:dae7123d432a 42 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
Adrian Suciu 24:dae7123d432a 43 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
Adrian Suciu 24:dae7123d432a 44 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Adrian Suciu 24:dae7123d432a 45 *
Adrian Suciu 24:dae7123d432a 46 ********************************************************************************/
Adrian Suciu 24:dae7123d432a 47
Adrian Suciu 24:dae7123d432a 48 #include <stdint.h>
Adrian Suciu 24:dae7123d432a 49 #include "mbed.h"
Adrian Suciu 24:dae7123d432a 50 #include "AD7790.h"
Adrian Suciu 24:dae7123d432a 51
Adrian Suciu 24:dae7123d432a 52 /**
Adrian Suciu 24:dae7123d432a 53 * @brief AD7790 constructor, sets CS pin and SPI format
Adrian Suciu 24:dae7123d432a 54 * @param CS - (optional)chip select of the AD7790
Adrian Suciu 24:dae7123d432a 55 * @param MOSI - (optional)pin of the SPI interface
Adrian Suciu 24:dae7123d432a 56 * @param MISO - (optional)pin of the SPI interface
Adrian Suciu 24:dae7123d432a 57 * @param SCK - (optional)pin of the SPI interface
Adrian Suciu 24:dae7123d432a 58 */
Adrian Suciu 24:dae7123d432a 59 AD7790::AD7790(float reference_voltage,
Adrian Suciu 24:dae7123d432a 60 PinName CS,
Adrian Suciu 24:dae7123d432a 61 PinName MOSI,
Adrian Suciu 24:dae7123d432a 62 PinName MISO,
Adrian Suciu 24:dae7123d432a 63 PinName SCK) :
Adrian Suciu 24:dae7123d432a 64 miso(MISO), ad7790(MOSI, MISO, SCK), cs(CS), _vref(reference_voltage), _PGA_gain(1)
Adrian Suciu 24:dae7123d432a 65 {
Adrian Suciu 24:dae7123d432a 66 cs = true; // cs is active low
Adrian Suciu 24:dae7123d432a 67 ad7790.format(8, _SPI_MODE);
Adrian Suciu 24:dae7123d432a 68 _continous_conversion = true;
Adrian Suciu 24:dae7123d432a 69 _channel = DIFFERENTIAL;
Adrian Suciu 24:dae7123d432a 70 }
Adrian Suciu 24:dae7123d432a 71
Adrian Suciu 24:dae7123d432a 72 /**
Adrian Suciu 24:dae7123d432a 73 * @brief Set AD7790 SPI frequency
Adrian Suciu 24:dae7123d432a 74 * @param hz - SPI bus frequency in hz
Adrian Suciu 24:dae7123d432a 75 * @return none
Adrian Suciu 24:dae7123d432a 76 */
Adrian Suciu 24:dae7123d432a 77 void AD7790::frequency(int hz)
Adrian Suciu 24:dae7123d432a 78 {
Adrian Suciu 24:dae7123d432a 79 ad7790.frequency(hz);
Adrian Suciu 24:dae7123d432a 80 }
Adrian Suciu 24:dae7123d432a 81
Adrian Suciu 24:dae7123d432a 82 /**
Adrian Suciu 24:dae7123d432a 83 * @brief Resets the AD7790
Adrian Suciu 24:dae7123d432a 84 * @return none
Adrian Suciu 24:dae7123d432a 85 */
Adrian Suciu 24:dae7123d432a 86 void AD7790::reset()
Adrian Suciu 24:dae7123d432a 87 {
Adrian Suciu 24:dae7123d432a 88 ad7790.format(8, _SPI_MODE);
Adrian Suciu 24:dae7123d432a 89 cs = false;
Adrian Suciu 24:dae7123d432a 90 wait_us(_DELAY_TIMING);
Adrian Suciu 24:dae7123d432a 91 ad7790.write(_RESET);
Adrian Suciu 24:dae7123d432a 92 ad7790.write(_RESET);
Adrian Suciu 24:dae7123d432a 93 ad7790.write(_RESET);
Adrian Suciu 24:dae7123d432a 94 ad7790.write(_RESET);
Adrian Suciu 24:dae7123d432a 95 wait_us(_DELAY_TIMING);
Adrian Suciu 24:dae7123d432a 96 cs = true;
Adrian Suciu 24:dae7123d432a 97 _continous_conversion = true;
Adrian Suciu 24:dae7123d432a 98 }
Adrian Suciu 24:dae7123d432a 99
Adrian Suciu 24:dae7123d432a 100 /**
Adrian Suciu 24:dae7123d432a 101 * Sets the mode register. Also sets continous mode and range based on the value
Adrian Suciu 24:dae7123d432a 102 * written in reg_val
Adrian Suciu 24:dae7123d432a 103 * @param reg_val
Adrian Suciu 24:dae7123d432a 104 */
Adrian Suciu 24:dae7123d432a 105 void AD7790::write_mode_reg(uint8_t reg_val)
Adrian Suciu 24:dae7123d432a 106 {
Adrian Suciu 24:dae7123d432a 107 write_reg(MODE_REG, reg_val);
Adrian Suciu 24:dae7123d432a 108 uint8_t continous_mode = (reg_val & 0xC0);
Adrian Suciu 24:dae7123d432a 109 if(continous_mode == 0x00) {
Adrian Suciu 24:dae7123d432a 110 _continous_conversion = true;
Adrian Suciu 24:dae7123d432a 111 } else {
Adrian Suciu 24:dae7123d432a 112 _continous_conversion = false;
Adrian Suciu 24:dae7123d432a 113 }
Adrian Suciu 24:dae7123d432a 114 uint8_t range = (reg_val & 0x30);
Adrian Suciu 24:dae7123d432a 115 _PGA_gain = 1 << (range >> 4);
Adrian Suciu 24:dae7123d432a 116 }
Adrian Suciu 24:dae7123d432a 117
Adrian Suciu 24:dae7123d432a 118 /**
Adrian Suciu 24:dae7123d432a 119 * Reads the mode register and returns its value
Adrian Suciu 24:dae7123d432a 120 * @return value of the mode register
Adrian Suciu 24:dae7123d432a 121 */
Adrian Suciu 24:dae7123d432a 122 uint8_t AD7790::read_mode_reg()
Adrian Suciu 24:dae7123d432a 123 {
Adrian Suciu 24:dae7123d432a 124 return read_reg(MODE_REG);
Adrian Suciu 24:dae7123d432a 125 }
Adrian Suciu 24:dae7123d432a 126
Adrian Suciu 24:dae7123d432a 127 /**
Adrian Suciu 24:dae7123d432a 128 * Writes the filter register
Adrian Suciu 24:dae7123d432a 129 * @param regValue value to be written.
Adrian Suciu 24:dae7123d432a 130 */
Adrian Suciu 24:dae7123d432a 131 void AD7790::write_filter_reg(uint8_t reg_val)
Adrian Suciu 24:dae7123d432a 132 {
Adrian Suciu 24:dae7123d432a 133 write_reg(FILTER_REG, reg_val);
Adrian Suciu 24:dae7123d432a 134 }
Adrian Suciu 24:dae7123d432a 135
Adrian Suciu 24:dae7123d432a 136 /**
Adrian Suciu 24:dae7123d432a 137 * Reads the filter register and returns its value
Adrian Suciu 24:dae7123d432a 138 * @return the value of the filter register
Adrian Suciu 24:dae7123d432a 139 */
Adrian Suciu 24:dae7123d432a 140 uint8_t AD7790::read_filter_reg()
Adrian Suciu 24:dae7123d432a 141 {
Adrian Suciu 24:dae7123d432a 142 return read_reg(FILTER_REG);
Adrian Suciu 24:dae7123d432a 143 }
Adrian Suciu 24:dae7123d432a 144
Adrian Suciu 24:dae7123d432a 145 /**
Adrian Suciu 24:dae7123d432a 146 * Reads the data register and returns its value
Adrian Suciu 24:dae7123d432a 147 * @return value of the data register
Adrian Suciu 24:dae7123d432a 148 */
Adrian Suciu 24:dae7123d432a 149 uint16_t AD7790::read_data_reg()
Adrian Suciu 24:dae7123d432a 150 {
Adrian Suciu 24:dae7123d432a 151 uint16_t data_result;
Adrian Suciu 24:dae7123d432a 152 ad7790.format(8, _SPI_MODE);
Adrian Suciu 24:dae7123d432a 153 cs = false;
Adrian Suciu 24:dae7123d432a 154 ad7790.write(_DATA_READ | (static_cast<uint8_t>(_channel)));
Adrian Suciu 24:dae7123d432a 155 data_result = ((ad7790.write(_DUMMY_BYTE)) << 8);
Adrian Suciu 24:dae7123d432a 156 data_result |= (ad7790.write(_DUMMY_BYTE));
Adrian Suciu 24:dae7123d432a 157 cs = true;
Adrian Suciu 24:dae7123d432a 158 return data_result;
Adrian Suciu 24:dae7123d432a 159 }
Adrian Suciu 24:dae7123d432a 160
Adrian Suciu 24:dae7123d432a 161 /**
Adrian Suciu 24:dae7123d432a 162 * Reads the status register of the ADC and returns its value
Adrian Suciu 24:dae7123d432a 163 * @return value of the status reg
Adrian Suciu 24:dae7123d432a 164 */
Adrian Suciu 24:dae7123d432a 165 uint8_t AD7790::read_status_reg()
Adrian Suciu 24:dae7123d432a 166 {
Adrian Suciu 24:dae7123d432a 167 return read_reg(STATUS_REG);
Adrian Suciu 24:dae7123d432a 168 }
Adrian Suciu 24:dae7123d432a 169
Adrian Suciu 24:dae7123d432a 170
Adrian Suciu 24:dae7123d432a 171 /**
Adrian Suciu 24:dae7123d432a 172 * @brief Enables/disables continous_conversion mode
Adrian Suciu 24:dae7123d432a 173 * In Single Conversion mode, read_u16 method will read the MODE register of the ADC,
Adrian Suciu 24:dae7123d432a 174 * then write the Start single conversion bit and wait for the DOUT/RDY pin to go low,
Adrian Suciu 24:dae7123d432a 175 * When the pin is driven low, data register is read back from the ADC.
Adrian Suciu 24:dae7123d432a 176 *
Adrian Suciu 24:dae7123d432a 177 * In Continous conversion mode, read_u16 method will poll the DOUT/RDY pin, if it is low,
Adrian Suciu 24:dae7123d432a 178 * the data register is read back from the ADC.
Adrian Suciu 24:dae7123d432a 179 *
Adrian Suciu 24:dae7123d432a 180 * @param mode
Adrian Suciu 24:dae7123d432a 181 * true - continous conversion mode enabled
Adrian Suciu 24:dae7123d432a 182 * false - single conversion mode enabled
Adrian Suciu 24:dae7123d432a 183 */
Adrian Suciu 24:dae7123d432a 184 void AD7790::set_conversion_mode(AD7790Mode_t mode)
Adrian Suciu 24:dae7123d432a 185 {
Adrian Suciu 24:dae7123d432a 186 uint8_t mode_reg_val;
Adrian Suciu 24:dae7123d432a 187 mode_reg_val = read_mode_reg() & 0x3F;
Adrian Suciu 24:dae7123d432a 188 mode_reg_val = mode_reg_val | (static_cast<uint8_t>(mode));
Adrian Suciu 24:dae7123d432a 189 write_mode_reg(mode);
Adrian Suciu 24:dae7123d432a 190 }
Adrian Suciu 24:dae7123d432a 191
Adrian Suciu 24:dae7123d432a 192 /**
Adrian Suciu 24:dae7123d432a 193 * - From mbed AnalogIn API -
Adrian Suciu 24:dae7123d432a 194 * @brief Read the input voltage, represented as an unsigned short in the range [0x0, 0xFFFF]
Adrian Suciu 24:dae7123d432a 195 * Depending on the conversion mode, this method will have different behavior. Conversion mode is set using
Adrian Suciu 24:dae7123d432a 196 * set_continous_conversion_mode(bool).
Adrian Suciu 24:dae7123d432a 197 *
Adrian Suciu 24:dae7123d432a 198 * In Single Conversion mode, read_u16 method will read the MODE register of the ADC,
Adrian Suciu 24:dae7123d432a 199 * then write the Start single conversion bit and wait for the DOUT/RDY pin to go low,
Adrian Suciu 24:dae7123d432a 200 * When the pin is driven low, data register is read back from the ADC.
Adrian Suciu 24:dae7123d432a 201 *
Adrian Suciu 24:dae7123d432a 202 * In Continous conversion mode, read_u16 method will poll the DOUT/RDY pin, if it is low,
Adrian Suciu 24:dae7123d432a 203 * the data register is read back from the ADC.
Adrian Suciu 24:dae7123d432a 204 *
Adrian Suciu 24:dae7123d432a 205 * @return 16-bit unsigned short representing the current input voltage, normalised to a 16-bit value
Adrian Suciu 24:dae7123d432a 206 * returns -1 (0xFFFF) along with a debug message if conversion failed.
Adrian Suciu 24:dae7123d432a 207 */
Adrian Suciu 24:dae7123d432a 208 uint16_t AD7790::read_u16(void)
Adrian Suciu 24:dae7123d432a 209 {
Adrian Suciu 24:dae7123d432a 210 uint16_t data_result = 0;
Adrian Suciu 24:dae7123d432a 211 ad7790.format(8, _SPI_MODE);
Adrian Suciu 24:dae7123d432a 212 cs = false;
Adrian Suciu 24:dae7123d432a 213 uint16_t timeout_cnt = 0;
Adrian Suciu 24:dae7123d432a 214 if(_continous_conversion == false) {
Adrian Suciu 24:dae7123d432a 215
Adrian Suciu 24:dae7123d432a 216 uint8_t mode_reg = read_mode_reg();
Adrian Suciu 24:dae7123d432a 217 wait_us(_DELAY_TIMING);
Adrian Suciu 24:dae7123d432a 218
Adrian Suciu 24:dae7123d432a 219 cs = false;
Adrian Suciu 24:dae7123d432a 220 mode_reg = (mode_reg & 0x3F) | MD1; // mask single conversion bits
Adrian Suciu 24:dae7123d432a 221 ad7790.write((MODE_REG << 4) | (static_cast<uint8_t>(_channel))); // start single conversion
Adrian Suciu 24:dae7123d432a 222 ad7790.write(mode_reg);
Adrian Suciu 24:dae7123d432a 223 timeout_cnt = _SINGLE_CONVERSION_TIMEOUT; // starts timeout
Adrian Suciu 24:dae7123d432a 224 } else {
Adrian Suciu 24:dae7123d432a 225 timeout_cnt = _CONTINOUS_CONVERSION_TIMEOUT; // starts timeout
Adrian Suciu 24:dae7123d432a 226 }
Adrian Suciu 24:dae7123d432a 227 wait_us(1);
Adrian Suciu 24:dae7123d432a 228
Adrian Suciu 24:dae7123d432a 229 while(miso) { // wait for the MISO pin to go low.
Adrian Suciu 24:dae7123d432a 230 if(timeout_cnt) {
Adrian Suciu 24:dae7123d432a 231 timeout_cnt--;
Adrian Suciu 24:dae7123d432a 232 } else {
Adrian Suciu 24:dae7123d432a 233 cs = true;
Adrian Suciu 24:dae7123d432a 234 #ifdef AD7790_DEBUG_MODE
Adrian Suciu 24:dae7123d432a 235 printf("timeout occurred reading the AD7790. "); // error, MISO line didn't toggle
Adrian Suciu 24:dae7123d432a 236 #endif
Adrian Suciu 24:dae7123d432a 237 return -1; // ERROR
Adrian Suciu 24:dae7123d432a 238 }
Adrian Suciu 24:dae7123d432a 239 wait_us(10);
Adrian Suciu 24:dae7123d432a 240 }
Adrian Suciu 24:dae7123d432a 241
Adrian Suciu 24:dae7123d432a 242 ad7790.write(_DATA_READ | (static_cast<uint8_t>(_channel)));
Adrian Suciu 24:dae7123d432a 243 data_result = ((ad7790.write(_DUMMY_BYTE)) << 8);
Adrian Suciu 24:dae7123d432a 244 data_result |= (ad7790.write(_DUMMY_BYTE));
Adrian Suciu 24:dae7123d432a 245 cs = true;
Adrian Suciu 24:dae7123d432a 246 return data_result;
Adrian Suciu 24:dae7123d432a 247 }
Adrian Suciu 24:dae7123d432a 248
Adrian Suciu 24:dae7123d432a 249 /**
Adrian Suciu 24:dae7123d432a 250 * @brief Reads a register of the AD7790
Adrian Suciu 24:dae7123d432a 251 * @param address - address of the register
Adrian Suciu 24:dae7123d432a 252 * @return value of the register
Adrian Suciu 24:dae7123d432a 253 */
Adrian Suciu 24:dae7123d432a 254 uint16_t AD7790::read_reg(AD7790Register_t address)
Adrian Suciu 24:dae7123d432a 255 {
Adrian Suciu 24:dae7123d432a 256 uint16_t data = address << 12;
Adrian Suciu 24:dae7123d432a 257 data |= _DUMMY_BYTE;
Adrian Suciu 24:dae7123d432a 258 data |= _READ_FLAG;
Adrian Suciu 24:dae7123d432a 259 data |= (static_cast<uint8_t>(_channel) << 8);
Adrian Suciu 24:dae7123d432a 260 return write_spi(data);
Adrian Suciu 24:dae7123d432a 261 }
Adrian Suciu 24:dae7123d432a 262
Adrian Suciu 24:dae7123d432a 263 /**
Adrian Suciu 24:dae7123d432a 264 * @brief Writes a register of the AD7790
Adrian Suciu 24:dae7123d432a 265 * @param address - address of the register
Adrian Suciu 24:dae7123d432a 266 * @param reg_val - value to be written
Adrian Suciu 24:dae7123d432a 267 * @return none
Adrian Suciu 24:dae7123d432a 268 *
Adrian Suciu 24:dae7123d432a 269 */
Adrian Suciu 24:dae7123d432a 270 void AD7790::write_reg(AD7790Register_t address, uint8_t reg_val)
Adrian Suciu 24:dae7123d432a 271 {
Adrian Suciu 24:dae7123d432a 272 uint16_t spi_data = address << 12;
Adrian Suciu 24:dae7123d432a 273 spi_data |= reg_val;
Adrian Suciu 24:dae7123d432a 274 spi_data |= (static_cast<uint8_t>(_channel) << 8);
Adrian Suciu 24:dae7123d432a 275 write_spi(spi_data);
Adrian Suciu 24:dae7123d432a 276 }
Adrian Suciu 24:dae7123d432a 277
Adrian Suciu 24:dae7123d432a 278 /**
Adrian Suciu 24:dae7123d432a 279 * @brief Writes 16bit data to the AD7790 SPI interface
Adrian Suciu 24:dae7123d432a 280 * @param reg_val to be written
Adrian Suciu 24:dae7123d432a 281 * @return data returned by the AD7790
Adrian Suciu 24:dae7123d432a 282 */
Adrian Suciu 24:dae7123d432a 283 uint16_t AD7790::write_spi(uint16_t reg_val)
Adrian Suciu 24:dae7123d432a 284 {
Adrian Suciu 24:dae7123d432a 285 uint16_t data_result;
Adrian Suciu 24:dae7123d432a 286 uint8_t upper_byte = (reg_val >> 8) & 0xFF;
Adrian Suciu 24:dae7123d432a 287 uint8_t lower_byte = reg_val & 0xFF;
Adrian Suciu 24:dae7123d432a 288 ad7790.format(8, _SPI_MODE);
Adrian Suciu 24:dae7123d432a 289 cs = false;
Adrian Suciu 24:dae7123d432a 290 data_result = (ad7790.write(upper_byte) << 8);
Adrian Suciu 24:dae7123d432a 291 data_result |= ad7790.write(lower_byte);
Adrian Suciu 24:dae7123d432a 292 cs = true;
Adrian Suciu 24:dae7123d432a 293 return data_result;
Adrian Suciu 24:dae7123d432a 294 }
Adrian Suciu 24:dae7123d432a 295
Adrian Suciu 24:dae7123d432a 296
Adrian Suciu 24:dae7123d432a 297 /**
Adrian Suciu 24:dae7123d432a 298 * Sets the AnalogInputRange to be used by the AD7790
Adrian Suciu 24:dae7123d432a 299 * @param range AnalogInputRange_t to be used in voltage computations
Adrian Suciu 24:dae7123d432a 300 */
Adrian Suciu 24:dae7123d432a 301 void AD7790::set_range(AnalogInputRange_t range)
Adrian Suciu 24:dae7123d432a 302 {
Adrian Suciu 24:dae7123d432a 303
Adrian Suciu 24:dae7123d432a 304 uint8_t mode_reg_val;
Adrian Suciu 24:dae7123d432a 305 mode_reg_val = read_mode_reg() & 0xCF;
Adrian Suciu 24:dae7123d432a 306 mode_reg_val = mode_reg_val | (range << 4);
Adrian Suciu 24:dae7123d432a 307 write_mode_reg(mode_reg_val);
Adrian Suciu 24:dae7123d432a 308 }
Adrian Suciu 24:dae7123d432a 309
Adrian Suciu 24:dae7123d432a 310 /**
Adrian Suciu 24:dae7123d432a 311 * Sets the reference voltage of the AD7790
Adrian Suciu 24:dae7123d432a 312 * @param ref reference voltage to be set
Adrian Suciu 24:dae7123d432a 313 */
Adrian Suciu 24:dae7123d432a 314 void AD7790::set_reference_voltage(float ref)
Adrian Suciu 24:dae7123d432a 315 {
Adrian Suciu 24:dae7123d432a 316 _vref = ref;
Adrian Suciu 24:dae7123d432a 317 }
Adrian Suciu 24:dae7123d432a 318
Adrian Suciu 24:dae7123d432a 319 /**
Adrian Suciu 24:dae7123d432a 320 * Gets the reference voltage of the AD7790
Adrian Suciu 24:dae7123d432a 321 * @return reference voltage
Adrian Suciu 24:dae7123d432a 322 */
Adrian Suciu 24:dae7123d432a 323 float AD7790::get_reference_voltage(void)
Adrian Suciu 24:dae7123d432a 324 {
Adrian Suciu 24:dae7123d432a 325 return _vref;
Adrian Suciu 24:dae7123d432a 326 }
Adrian Suciu 24:dae7123d432a 327
Adrian Suciu 24:dae7123d432a 328 /**
Adrian Suciu 24:dae7123d432a 329 * Reads the data register of the ADC and converts the result to volts
Adrian Suciu 24:dae7123d432a 330 * Gain needs to be correctly set using set_gain in order to get accurate results
Adrian Suciu 24:dae7123d432a 331 * @return voltage of the ADC input
Adrian Suciu 24:dae7123d432a 332 */
Adrian Suciu 24:dae7123d432a 333 float AD7790::read_voltage(void)
Adrian Suciu 24:dae7123d432a 334 {
Adrian Suciu 24:dae7123d432a 335 return data_to_voltage(read_u16());
Adrian Suciu 24:dae7123d432a 336 }
Adrian Suciu 24:dae7123d432a 337
Adrian Suciu 24:dae7123d432a 338 /**
Adrian Suciu 24:dae7123d432a 339 * Converts an uint16_t to voltage.
Adrian Suciu 24:dae7123d432a 340 * Gain needs to be correctly set using set_gain in order to get accurate results
Adrian Suciu 24:dae7123d432a 341 * @param data in uint16_t format
Adrian Suciu 24:dae7123d432a 342 * @return float value of voltage (in V)
Adrian Suciu 24:dae7123d432a 343 */
Adrian Suciu 24:dae7123d432a 344 float AD7790::data_to_voltage(uint16_t data)
Adrian Suciu 24:dae7123d432a 345 {
Adrian Suciu 24:dae7123d432a 346 return ((data / static_cast<float>(_RESOLUTION / 2)) - 1) * (_vref / _PGA_gain);
Adrian Suciu 24:dae7123d432a 347 }
Adrian Suciu 24:dae7123d432a 348
Adrian Suciu 24:dae7123d432a 349 /**
Adrian Suciu 24:dae7123d432a 350 * Converts voltage to an uint16_t.
Adrian Suciu 24:dae7123d432a 351 * Gain needs to be correctly set using set_gain in order to get accurate results
Adrian Suciu 24:dae7123d432a 352 * @param voltage to be converted
Adrian Suciu 24:dae7123d432a 353 * @return data in uint16_t format
Adrian Suciu 24:dae7123d432a 354 */
Adrian Suciu 24:dae7123d432a 355 uint16_t AD7790::voltage_to_data(float voltage)
Adrian Suciu 24:dae7123d432a 356 {
Adrian Suciu 24:dae7123d432a 357 return (((voltage * _PGA_gain / _vref) + 1) * static_cast<float>(_RESOLUTION / 2));
Adrian Suciu 24:dae7123d432a 358 }
Adrian Suciu 24:dae7123d432a 359
Adrian Suciu 24:dae7123d432a 360 /**
Adrian Suciu 24:dae7123d432a 361 * Sets the conversion channel.
Adrian Suciu 24:dae7123d432a 362 * @param channel
Adrian Suciu 24:dae7123d432a 363 */
Adrian Suciu 24:dae7123d432a 364 void AD7790::set_channel(AD7790Channel_t channel)
Adrian Suciu 24:dae7123d432a 365 {
Adrian Suciu 24:dae7123d432a 366 _channel = channel;
Adrian Suciu 24:dae7123d432a 367 }
Adrian Suciu 24:dae7123d432a 368
Adrian Suciu 24:dae7123d432a 369 /**
Adrian Suciu 24:dae7123d432a 370 * - From mbed AnalogIn API -
Adrian Suciu 24:dae7123d432a 371 * Read the input voltage, represented as a float in the range [0.0, 1.0] - uses the read_u16 method
Adrian Suciu 24:dae7123d432a 372 * @returns A floating-point value representing the current input voltage, measured as a percentage
Adrian Suciu 24:dae7123d432a 373 * returns 1.0 along with a debug message if the conversion failed
Adrian Suciu 24:dae7123d432a 374 */
Adrian Suciu 24:dae7123d432a 375 float AD7790::read(void)
Adrian Suciu 24:dae7123d432a 376 {
Adrian Suciu 24:dae7123d432a 377 float percent;
Adrian Suciu 24:dae7123d432a 378 uint16_t data;
Adrian Suciu 24:dae7123d432a 379 data = read_u16();
Adrian Suciu 24:dae7123d432a 380 percent = (data / static_cast<float>(_RESOLUTION) ); // translate bipolar conversion to [0.0, 1.0] domain
Adrian Suciu 24:dae7123d432a 381 return percent;
Adrian Suciu 24:dae7123d432a 382 }
Adrian Suciu 24:dae7123d432a 383
Adrian Suciu 24:dae7123d432a 384 #ifdef MBED_OPERATORS
Adrian Suciu 24:dae7123d432a 385
Adrian Suciu 24:dae7123d432a 386 /**
Adrian Suciu 24:dae7123d432a 387 * - From mbed AnalogIn API -
Adrian Suciu 24:dae7123d432a 388 * An operator shorthand for read()
Adrian Suciu 24:dae7123d432a 389 * The float() operator can be used as a shorthand for read() to simplify common code sequences
Adrian Suciu 24:dae7123d432a 390 */
Adrian Suciu 24:dae7123d432a 391 AD7790::operator float()
Adrian Suciu 24:dae7123d432a 392 {
Adrian Suciu 24:dae7123d432a 393 return read();
Adrian Suciu 24:dae7123d432a 394 }
Adrian Suciu 24:dae7123d432a 395
Adrian Suciu 24:dae7123d432a 396 #endif
Adrian Suciu 24:dae7123d432a 397
Adrian Suciu 24:dae7123d432a 398
Adrian Suciu 24:dae7123d432a 399