Driver for the AD5270 digipot
Dependents: ad5270-helloworld CN0357 CN0396
For additional information check out the mbed page of the Analog Devices wiki: https://wiki.analog.com/resources/tools-software/mbed-drivers-all
AD5270.cpp
- Committer:
- adisuciu
- Date:
- 2016-08-18
- Revision:
- 1:9f9dd8c48e8a
- Parent:
- 0:18d434f6f122
File content as of revision 1:9f9dd8c48e8a:
/** * @file AD5270.cpp * @brief Source file for AD5270 rheostat * @author Analog Devices Inc. * * For support please go to: * Github: https://github.com/analogdevicesinc/mbed-adi * Support: https://ez.analog.com/community/linux-device-drivers/microcontroller-no-os-drivers * Product: http://www.analog.com/ad5270 * More: https://wiki.analog.com/resources/tools-software/mbed-drivers-all ******************************************************************************** * Copyright 2016(c) Analog Devices, Inc. * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * - Neither the name of Analog Devices, Inc. nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * - The use of this software may or may not infringe the patent rights * of one or more patent holders. This license does not release you * from the requirement that you obtain separate licenses from these * patent holders to use this software. * - Use of the software either in source or binary form, must be run * on or directly connected to an Analog Devices Inc. component. * * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ********************************************************************************/ #include "mbed.h" #include "AD5270.h" /** * @brief AD5270 constructor, sets CS pin and SPI format * @param CS - (optional)chip select of the AD5270 * @param max_resistance - (optional) nominal resistance of the AD5270 chip in ohms * @param MOSI - (optional)pin of the SPI interface * @param MISO - (optional)pin of the SPI interface * @param SCK - (optional)pin of the SPI interface */ AD5270::AD5270(PinName CS, float max_resistance, PinName MOSI, PinName MISO, PinName SCK): ad5270(MOSI, MISO, SCK), cs(CS), _max_resistance(max_resistance) { cs = true; ad5270.format(8, _SPI_MODE); } /** * @brief Compute for the nearest RDAC value from given resistance * @param resistance - resistor * @return RDAC value - closest possible to given resistance */ uint16_t AD5270::calc_RDAC(float resistance) { return static_cast<uint16_t>( (resistance / _max_resistance) * 1024.0 ); } /** * @brief sets a new value for the RDAC * @param resistance new value for the resistance * @return actual value of the resistance in the RDAC */ float AD5270::write_RDAC(float resistance) { // Compute for the RDAC code nearest to the required feedback resistance uint16_t RDAC_val = calc_RDAC(resistance); float RDAC_Value = ((static_cast<float> (RDAC_val) * _max_resistance) / 1024.0); // inverse operation to get actual resistance in the RDAC write_wiper_reg(RDAC_val); return RDAC_Value; } /** * Reads the RDAC register * @return RDAC resistor value */ float AD5270::read_RDAC() { uint16_t RDAC_val = read_wiper_reg(); return ((static_cast<float> (RDAC_val) * _max_resistance) / 1024.0); } /** * @brief Puts the AD5270 SDO line in to Hi-Z mode * @return none */ void AD5270::set_SDO_HiZ(void) { write_reg(HI_Z_Cmd); wait_us(2); write_reg(NO_OP_cmd); } /** * @brief Set AD5270 SPI frequency * @param hz - SPI bus frequency in hz * @return none */ void AD5270::frequency(int hz) { ad5270.frequency(hz); } /** * @brief Issues AD5270 a command * @param command - command to be sent * @param data - (optional)value for the requested command * @return response form the AD5270 */ uint16_t AD5270::write_cmd(uint8_t command, uint16_t data, bool toggle_cs) { /* build 16 bit data to be written - Command + Value */ uint16_t ui16Command = ((command & 0x3C) << 8) | (data & 0x3FF); return write_reg(ui16Command, toggle_cs); } /** * Enables the 50TP memory programming */ void AD5270::enable_50TP_programming() { uint8_t regVal = read_ctrl_reg(); write_cmd(WRITE_CTRL_REG, regVal | PROGRAM_50TP_ENABLE); // RDAC register write protect - allow update of wiper position through digital interface } /** * Stores current RDAC content to the 50TP memory */ void AD5270::store_50TP() { write_cmd(STORE_50TP); wait_ms(_WRITE_OPERATION_50TP_TIMEOUT); } /** * Disables the 50TP memory programming */ void AD5270::disable_50TP_programming() { uint8_t regVal = read_ctrl_reg(); write_cmd(WRITE_CTRL_REG, regVal & (~PROGRAM_50TP_ENABLE)); } /** * @brief Writes 16bit data to the AD5270 SPI interface * @param data to be written * @return data returned by the AD5270 */ uint16_t AD5270::write_reg(uint16_t data, bool toggle_cs) { uint16_t result; uint8_t upper_byte = (data >> 8) & 0xFF; uint8_t lower_byte = data & 0xFF; ad5270.format(8, _SPI_MODE); cs = false & toggle_cs; result = ((ad5270.write(upper_byte)) << 8); result |= ad5270.write(lower_byte); cs = true & toggle_cs; return result; } /** * @brief Gets maximum resistance of the AD5270 digital rheostat * @return maximum resistance in ohms */ float AD5270::get_max_resistance() { return _max_resistance; } /** * Writes the wiper register. This includes reading the control register, * setting write protect off, writing the wiper, and reverting the settings * to the control reg. * @param data to be written */ void AD5270::write_wiper_reg(uint16_t data) { uint8_t reg_val = read_ctrl_reg(); write_cmd(WRITE_CTRL_REG, reg_val | RDAC_WRITE_PROTECT); // RDAC register write protect - allow update of wiper position through digital interface write_cmd(WRITE_RDAC, data); // write data to the RDAC register write_cmd(WRITE_CTRL_REG, reg_val); // RDAC register write protect - allow update of wiper position through digital interface } /** * Reads the wiper register value * @return value of the wiper register */ uint16_t AD5270::read_wiper_reg(void) { uint16_t RDAC_val; write_cmd(READ_RDAC); wait_us(_REG_OPERATION_TIMEOUT); RDAC_val = write_cmd(NO_OP); return RDAC_val; } /** * Reads the last programmed value of the 50TP memory * @return last programmed value */ uint8_t AD5270::read_50TP_last_address(void) { uint8_t ret_val; write_cmd(READ_50TP_ADDRESS); wait_us(_MEMORY_OPERATION_TIMEOUT); ret_val = write_cmd(NO_OP); return ret_val; } /** * Reads the content of a 50TP memory address * @param address memory to be read * @return value stored in the 50TP address */ uint16_t AD5270::read_50TP_memory(uint8_t address) { uint16_t ret_val; write_cmd(READ_50TP_CONTENTS, address); wait_us(_MEMORY_OPERATION_TIMEOUT); ret_val = write_cmd(NO_OP); return ret_val; } /** * Writes the control register * @param data to be written */ void AD5270::write_ctrl_reg(uint8_t data) { write_cmd(WRITE_CTRL_REG, data); } /** * Reads the control register * @return value of the control register */ uint8_t AD5270::read_ctrl_reg(void) { uint8_t ret_val; write_cmd(READ_CTRL_REG); wait_us(_REG_OPERATION_TIMEOUT); ret_val = write_cmd(NO_OP); return ret_val; } /** * Resets the wiper register value to the data last written in the 50TP */ void AD5270::reset_RDAC(void) { write_cmd(SW_RST); } /** * Changes the device mode, enabled or shutdown * @param mode - new mode of the device */ void AD5270::change_mode(AD5270Modes_t mode) { write_cmd(SW_SHUTDOWN, static_cast<uint8_t>(mode)); } void AD5270::daisy_chain(uint8_t *buffer, uint8_t size) { cs = 0; for(int i = 0; i < size; i++) buffer[i] = ad5270.write(buffer[i]); cs = 1; }