Diff: AD5270.cpp

Revision:

0:18d434f6f122

Child:

1:9f9dd8c48e8a

diff -r 000000000000 -r 18d434f6f122 AD5270.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AD5270.cpp	Tue May 03 12:55:30 2016 +0000
@@ -0,0 +1,283 @@
+/**
+*   @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)
+{
+    /* build 16 bit data to be written - Command + Value */
+    uint16_t ui16Command = ((command & 0x3C) << 8) | (data & 0x3FF);
+    return write_reg(ui16Command);
+}
+
+/**
+ *  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)
+{
+    uint16_t result;
+    uint8_t upper_byte = (data >> 8) & 0xFF;
+    uint8_t lower_byte =  data & 0xFF;
+    ad5270.format(8, _SPI_MODE);
+    cs = false;
+    result  = ((ad5270.write(upper_byte)) << 8);
+    result |=   ad5270.write(lower_byte);
+    cs = true;
+    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));
+}
+
+
+