A collection of Analog Devices drivers for the mbed platform
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AD5270.cpp
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00001 /** 00002 * @file AD5270.cpp 00003 * @brief Source file for AD5270 rheostat 00004 * @author Analog Devices Inc. 00005 * 00006 * For support please go to: 00007 * Github: https://github.com/analogdevicesinc/mbed-adi 00008 * Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers 00009 * Product: http://www.analog.com/ad5270 00010 * More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all 00011 00012 ******************************************************************************** 00013 * Copyright 2016(c) Analog Devices, Inc. 00014 * 00015 * All rights reserved. 00016 * 00017 * Redistribution and use in source and binary forms, with or without 00018 * modification, are permitted provided that the following conditions are met: 00019 * - Redistributions of source code must retain the above copyright 00020 * notice, this list of conditions and the following disclaimer. 00021 * - Redistributions in binary form must reproduce the above copyright 00022 * notice, this list of conditions and the following disclaimer in 00023 * the documentation and/or other materials provided with the 00024 * distribution. 00025 * - Neither the name of Analog Devices, Inc. nor the names of its 00026 * contributors may be used to endorse or promote products derived 00027 * from this software without specific prior written permission. 00028 * - The use of this software may or may not infringe the patent rights 00029 * of one or more patent holders. This license does not release you 00030 * from the requirement that you obtain separate licenses from these 00031 * patent holders to use this software. 00032 * - Use of the software either in source or binary form, must be run 00033 * on or directly connected to an Analog Devices Inc. component. 00034 * 00035 * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR 00036 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, 00037 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 00038 * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, 00039 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00040 * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR 00041 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 00042 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00043 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00044 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00045 * 00046 ********************************************************************************/ 00047 00048 00049 #include "mbed.h" 00050 #include "AD5270.h" 00051 00052 /** 00053 * @brief AD5270 constructor, sets CS pin and SPI format 00054 * @param CS - (optional)chip select of the AD5270 00055 * @param max_resistance - (optional) nominal resistance of the AD5270 chip in ohms 00056 * @param MOSI - (optional)pin of the SPI interface 00057 * @param MISO - (optional)pin of the SPI interface 00058 * @param SCK - (optional)pin of the SPI interface 00059 */ 00060 AD5270::AD5270(PinName CS, float max_resistance, PinName MOSI, PinName MISO, PinName SCK): 00061 ad5270(MOSI, MISO, SCK), cs(CS), _max_resistance(max_resistance) 00062 { 00063 cs = true; 00064 ad5270.format(8, _SPI_MODE); 00065 } 00066 00067 /** 00068 * @brief Compute for the nearest RDAC value from given resistance 00069 * @param resistance - resistor 00070 * @return RDAC value - closest possible to given resistance 00071 */ 00072 uint16_t AD5270::calc_RDAC(float resistance) 00073 { 00074 return static_cast<uint16_t>( (resistance / _max_resistance) * 1024.0 ); 00075 } 00076 00077 /** 00078 * @brief sets a new value for the RDAC 00079 * @param resistance new value for the resistance 00080 * @return actual value of the resistance in the RDAC 00081 */ 00082 float AD5270::write_RDAC(float resistance) 00083 { 00084 // Compute for the RDAC code nearest to the required feedback resistance 00085 uint16_t RDAC_val = calc_RDAC(resistance); 00086 float RDAC_Value = ((static_cast<float> (RDAC_val) * _max_resistance) / 1024.0); // inverse operation to get actual resistance in the RDAC 00087 write_wiper_reg(RDAC_val); 00088 return RDAC_Value; 00089 } 00090 00091 /** 00092 * Reads the RDAC register 00093 * @return RDAC resistor value 00094 */ 00095 float AD5270::read_RDAC() 00096 { 00097 uint16_t RDAC_val = read_wiper_reg(); 00098 return ((static_cast<float> (RDAC_val) * _max_resistance) / 1024.0); 00099 } 00100 00101 /** 00102 * @brief Puts the AD5270 SDO line in to Hi-Z mode 00103 * @return none 00104 */ 00105 void AD5270::set_SDO_HiZ(void) 00106 { 00107 write_reg(HI_Z_Cmd); 00108 wait_us(2); 00109 write_reg(NO_OP_cmd); 00110 } 00111 00112 /** 00113 * @brief Set AD5270 SPI frequency 00114 * @param hz - SPI bus frequency in hz 00115 * @return none 00116 */ 00117 void AD5270::frequency(int hz) 00118 { 00119 ad5270.frequency(hz); 00120 } 00121 00122 /** 00123 * @brief Issues AD5270 a command 00124 * @param command - command to be sent 00125 * @param data - (optional)value for the requested command 00126 * @return response form the AD5270 00127 */ 00128 uint16_t AD5270::write_cmd(uint8_t command, uint16_t data, bool toggle_cs) 00129 { 00130 /* build 16 bit data to be written - Command + Value */ 00131 uint16_t ui16Command = ((command & 0x3C) << 8) | (data & 0x3FF); 00132 return write_reg(ui16Command, toggle_cs); 00133 } 00134 00135 /** 00136 * Enables the 50TP memory programming 00137 */ 00138 void AD5270::enable_50TP_programming() 00139 { 00140 uint8_t regVal = read_ctrl_reg(); 00141 write_cmd(WRITE_CTRL_REG, regVal | PROGRAM_50TP_ENABLE); // RDAC register write protect - allow update of wiper position through digital interface 00142 } 00143 00144 /** 00145 * Stores current RDAC content to the 50TP memory 00146 */ 00147 void AD5270::store_50TP() 00148 { 00149 write_cmd(STORE_50TP); 00150 wait_ms(_WRITE_OPERATION_50TP_TIMEOUT); 00151 } 00152 00153 /** 00154 * Disables the 50TP memory programming 00155 */ 00156 void AD5270::disable_50TP_programming() 00157 { 00158 uint8_t regVal = read_ctrl_reg(); 00159 write_cmd(WRITE_CTRL_REG, regVal & (~PROGRAM_50TP_ENABLE)); 00160 } 00161 00162 /** 00163 * @brief Writes 16bit data to the AD5270 SPI interface 00164 * @param data to be written 00165 * @return data returned by the AD5270 00166 */ 00167 uint16_t AD5270::write_reg(uint16_t data, bool toggle_cs) 00168 { 00169 uint16_t result; 00170 uint8_t upper_byte = (data >> 8) & 0xFF; 00171 uint8_t lower_byte = data & 0xFF; 00172 ad5270.format(8, _SPI_MODE); 00173 cs = false & toggle_cs; 00174 result = ((ad5270.write(upper_byte)) << 8); 00175 result |= ad5270.write(lower_byte); 00176 cs = true & toggle_cs; 00177 return result; 00178 } 00179 00180 /** 00181 * @brief Gets maximum resistance of the AD5270 digital rheostat 00182 * @return maximum resistance in ohms 00183 */ 00184 float AD5270::get_max_resistance() 00185 { 00186 return _max_resistance; 00187 } 00188 00189 /** 00190 * Writes the wiper register. This includes reading the control register, 00191 * setting write protect off, writing the wiper, and reverting the settings 00192 * to the control reg. 00193 * @param data to be written 00194 */ 00195 void AD5270::write_wiper_reg(uint16_t data) 00196 { 00197 uint8_t reg_val = read_ctrl_reg(); 00198 write_cmd(WRITE_CTRL_REG, reg_val | RDAC_WRITE_PROTECT); // RDAC register write protect - allow update of wiper position through digital interface 00199 write_cmd(WRITE_RDAC, data); // write data to the RDAC register 00200 write_cmd(WRITE_CTRL_REG, reg_val); // RDAC register write protect - allow update of wiper position through digital interface 00201 } 00202 00203 /** 00204 * Reads the wiper register value 00205 * @return value of the wiper register 00206 */ 00207 uint16_t AD5270::read_wiper_reg(void) 00208 { 00209 uint16_t RDAC_val; 00210 write_cmd(READ_RDAC); 00211 wait_us(_REG_OPERATION_TIMEOUT); 00212 RDAC_val = write_cmd(NO_OP); 00213 return RDAC_val; 00214 } 00215 00216 /** 00217 * Reads the last programmed value of the 50TP memory 00218 * @return last programmed value 00219 */ 00220 uint8_t AD5270::read_50TP_last_address(void) 00221 { 00222 uint8_t ret_val; 00223 write_cmd(READ_50TP_ADDRESS); 00224 wait_us(_MEMORY_OPERATION_TIMEOUT); 00225 ret_val = write_cmd(NO_OP); 00226 return ret_val; 00227 } 00228 00229 /** 00230 * Reads the content of a 50TP memory address 00231 * @param address memory to be read 00232 * @return value stored in the 50TP address 00233 */ 00234 uint16_t AD5270::read_50TP_memory(uint8_t address) 00235 { 00236 uint16_t ret_val; 00237 write_cmd(READ_50TP_CONTENTS, address); 00238 wait_us(_MEMORY_OPERATION_TIMEOUT); 00239 ret_val = write_cmd(NO_OP); 00240 return ret_val; 00241 } 00242 00243 /** 00244 * Writes the control register 00245 * @param data to be written 00246 */ 00247 void AD5270::write_ctrl_reg(uint8_t data) 00248 { 00249 write_cmd(WRITE_CTRL_REG, data); 00250 } 00251 00252 /** 00253 * Reads the control register 00254 * @return value of the control register 00255 */ 00256 uint8_t AD5270::read_ctrl_reg(void) 00257 { 00258 uint8_t ret_val; 00259 write_cmd(READ_CTRL_REG); 00260 wait_us(_REG_OPERATION_TIMEOUT); 00261 ret_val = write_cmd(NO_OP); 00262 return ret_val; 00263 } 00264 00265 /** 00266 * Resets the wiper register value to the data last written in the 50TP 00267 */ 00268 void AD5270::reset_RDAC(void) 00269 { 00270 write_cmd(SW_RST); 00271 } 00272 00273 /** 00274 * Changes the device mode, enabled or shutdown 00275 * @param mode - new mode of the device 00276 */ 00277 void AD5270::change_mode(AD5270Modes_t mode) 00278 { 00279 write_cmd(SW_SHUTDOWN, static_cast<uint8_t>(mode)); 00280 } 00281 00282 void AD5270::daisy_chain(uint8_t *buffer, uint8_t size) 00283 { 00284 cs = 0; 00285 for(int i = 0; i < size; i++) 00286 buffer[i] = ad5270.write(buffer[i]); 00287 cs = 1; 00288 } 00289
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