John Garlitos / LTC26X6

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ltc26x6.c@1:cab5535713ee, 2021-12-06 (annotated)

Committer:
jngarlitos
Date:
Mon Dec 06 05:17:03 2021 +0000
Revision:
1:cab5535713ee
Initial Commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jngarlitos 1:cab5535713ee 1 /***************************************************************************//**
jngarlitos 1:cab5535713ee 2 * @file ltc26x6.c
jngarlitos 1:cab5535713ee 3 * @brief Implementation of LTC2606,LTC2616,LTC2626 Driver.
jngarlitos 1:cab5535713ee 4 ********************************************************************************
jngarlitos 1:cab5535713ee 5 * Copyright 2021(c) Analog Devices, Inc.
jngarlitos 1:cab5535713ee 6 *
jngarlitos 1:cab5535713ee 7 * All rights reserved.
jngarlitos 1:cab5535713ee 8 *
jngarlitos 1:cab5535713ee 9 * Redistribution and use in source and binary forms, with or without
jngarlitos 1:cab5535713ee 10 * modification, are permitted provided that the following conditions are met:
jngarlitos 1:cab5535713ee 11 * - Redistributions of source code must retain the above copyright
jngarlitos 1:cab5535713ee 12 * notice, this list of conditions and the following disclaimer.
jngarlitos 1:cab5535713ee 13 * - Redistributions in binary form must reproduce the above copyright
jngarlitos 1:cab5535713ee 14 * notice, this list of conditions and the following disclaimer in
jngarlitos 1:cab5535713ee 15 * the documentation and/or other materials provided with the
jngarlitos 1:cab5535713ee 16 * distribution.
jngarlitos 1:cab5535713ee 17 * - Neither the name of Analog Devices, Inc. nor the names of its
jngarlitos 1:cab5535713ee 18 * contributors may be used to endorse or promote products derived
jngarlitos 1:cab5535713ee 19 * from this software without specific prior written permission.
jngarlitos 1:cab5535713ee 20 * - The use of this software may or may not infringe the patent rights
jngarlitos 1:cab5535713ee 21 * of one or more patent holders. This license does not release you
jngarlitos 1:cab5535713ee 22 * from the requirement that you obtain separate licenses from these
jngarlitos 1:cab5535713ee 23 * patent holders to use this software.
jngarlitos 1:cab5535713ee 24 * - Use of the software either in source or binary form, must be run
jngarlitos 1:cab5535713ee 25 * on or directly connected to an Analog Devices Inc. component.
jngarlitos 1:cab5535713ee 26 *
jngarlitos 1:cab5535713ee 27 * THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR
jngarlitos 1:cab5535713ee 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT,
jngarlitos 1:cab5535713ee 29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
jngarlitos 1:cab5535713ee 30 * IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT,
jngarlitos 1:cab5535713ee 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
jngarlitos 1:cab5535713ee 32 * LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR
jngarlitos 1:cab5535713ee 33 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
jngarlitos 1:cab5535713ee 34 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
jngarlitos 1:cab5535713ee 35 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
jngarlitos 1:cab5535713ee 36 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
jngarlitos 1:cab5535713ee 37 *******************************************************************************/
jngarlitos 1:cab5535713ee 38
jngarlitos 1:cab5535713ee 39 #include <stdio.h>
jngarlitos 1:cab5535713ee 40 #include <stdint.h>
jngarlitos 1:cab5535713ee 41 #include <stdlib.h>
jngarlitos 1:cab5535713ee 42 #include <math.h>
jngarlitos 1:cab5535713ee 43
jngarlitos 1:cab5535713ee 44 #include "ltc26x6.h"
jngarlitos 1:cab5535713ee 45
jngarlitos 1:cab5535713ee 46 /**
jngarlitos 1:cab5535713ee 47 * Initialize the device.
jngarlitos 1:cab5535713ee 48 * @param device - The device structure.
jngarlitos 1:cab5535713ee 49 * @param init_param - The structure that contains the device initial
jngarlitos 1:cab5535713ee 50 * parameters.
jngarlitos 1:cab5535713ee 51 * @return 0 in case of success, negative error code otherwise.
jngarlitos 1:cab5535713ee 52 */
jngarlitos 1:cab5535713ee 53 int32_t ltc26x6_init(struct ltc26x6_dev **device,
jngarlitos 1:cab5535713ee 54 struct ltc26x6_init_param init_param)
jngarlitos 1:cab5535713ee 55 {
jngarlitos 1:cab5535713ee 56 struct ltc26x6_dev *dev;
jngarlitos 1:cab5535713ee 57 int32_t ret;
jngarlitos 1:cab5535713ee 58
jngarlitos 1:cab5535713ee 59 dev = (struct ltc26x6_dev *)malloc(sizeof(*dev));
jngarlitos 1:cab5535713ee 60 if (!dev)
jngarlitos 1:cab5535713ee 61 return -1;
jngarlitos 1:cab5535713ee 62
jngarlitos 1:cab5535713ee 63 ret = i2c_init(&dev->i2c_desc, &init_param.i2c_init);
jngarlitos 1:cab5535713ee 64 dev->resolution = init_param.resolution;
jngarlitos 1:cab5535713ee 65 dev->vref = init_param.vref;
jngarlitos 1:cab5535713ee 66 dev->typical_offset = init_param.typical_offset;
jngarlitos 1:cab5535713ee 67 *device = dev;
jngarlitos 1:cab5535713ee 68 return ret;
jngarlitos 1:cab5535713ee 69 }
jngarlitos 1:cab5535713ee 70
jngarlitos 1:cab5535713ee 71 /**
jngarlitos 1:cab5535713ee 72 * Calculates an LTC26X6 DAC code for the desired output voltage.
jngarlitos 1:cab5535713ee 73 * Based on the desired output voltage, the offset, and lsb parameters, return the corresponding DAC code that should be written to the LTC26X6.
jngarlitos 1:cab5535713ee 74 * @param dac_voltage Desired output voltage
jngarlitos 1:cab5535713ee 75 * @param *code Returned DAC code
jngarlitos 1:cab5535713ee 76 * @return 0 in case of success, negative error code otherwise.
jngarlitos 1:cab5535713ee 77 */
jngarlitos 1:cab5535713ee 78 int16_t ltc26x6_voltage_to_code(struct ltc26x6_dev *device, float dac_voltage,
jngarlitos 1:cab5535713ee 79 uint16_t *code)
jngarlitos 1:cab5535713ee 80 {
jngarlitos 1:cab5535713ee 81 uint32_t ltc26x6_full_scale = (2 << device->resolution) - 1;
jngarlitos 1:cab5535713ee 82 // The LTC26X6 least significant bit value with given voltage reference
jngarlitos 1:cab5535713ee 83 float ltc26x6_lsb = (float)(device->vref/ltc26x6_full_scale);
jngarlitos 1:cab5535713ee 84 int32_t dac_code, ret;
jngarlitos 1:cab5535713ee 85 float float_code;
jngarlitos 1:cab5535713ee 86
jngarlitos 1:cab5535713ee 87 // 1) Calculate the DAC code: (DAC voltage/LSB)- typical offset volatge
jngarlitos 1:cab5535713ee 88 float_code = (dac_voltage / ltc26x6_lsb) - device->typical_offset;
jngarlitos 1:cab5535713ee 89 // 2) Round
jngarlitos 1:cab5535713ee 90 float_code = (float_code > (floor(float_code) + 0.5)) ? ceil(float_code) : floor(float_code);
jngarlitos 1:cab5535713ee 91 // 3) Convert to unsigned integer
jngarlitos 1:cab5535713ee 92 dac_code = (int32_t)(float_code);
jngarlitos 1:cab5535713ee 93
jngarlitos 1:cab5535713ee 94 if(dac_code > ltc26x6_full_scale) {
jngarlitos 1:cab5535713ee 95 // Requesetd voltage is bigger than reference voltage
jngarlitos 1:cab5535713ee 96 // Return fullscale code
jngarlitos 1:cab5535713ee 97 dac_code = ltc26x6_full_scale;
jngarlitos 1:cab5535713ee 98 // Return Overflow error
jngarlitos 1:cab5535713ee 99 ret = LTC26X6_CODE_OVERFLOW;
jngarlitos 1:cab5535713ee 100 } else if(dac_code < 0) {
jngarlitos 1:cab5535713ee 101 // Requested voltage is lower than offset voltage
jngarlitos 1:cab5535713ee 102 dac_code = 0;
jngarlitos 1:cab5535713ee 103 // Return Underflow error
jngarlitos 1:cab5535713ee 104 ret = LTC26X6_CODE_UNDERFLOW;
jngarlitos 1:cab5535713ee 105 } else // Requestedd volage is in supported range
jngarlitos 1:cab5535713ee 106 ret = SUCCESS;
jngarlitos 1:cab5535713ee 107
jngarlitos 1:cab5535713ee 108 *code = ((uint16_t)(dac_code));
jngarlitos 1:cab5535713ee 109 return ret;
jngarlitos 1:cab5535713ee 110 }
jngarlitos 1:cab5535713ee 111
jngarlitos 1:cab5535713ee 112 /**
jngarlitos 1:cab5535713ee 113 * Write code to LTC26X6
jngarlitos 1:cab5535713ee 114 * @param dev The device structure.
jngarlitos 1:cab5535713ee 115 * @param dac_command Command for the DAC
jngarlitos 1:cab5535713ee 116 * Accepted values: write_command
jngarlitos 1:cab5535713ee 117 * write_update_command
jngarlitos 1:cab5535713ee 118 *
jngarlitos 1:cab5535713ee 119 * @param dac_code 16-bit DAC output voltage code
jngarlitos 1:cab5535713ee 120 * @return 0 in case of success, negative error code otherwise.
jngarlitos 1:cab5535713ee 121 */
jngarlitos 1:cab5535713ee 122 int32_t ltc26x6_write_code(struct ltc26x6_dev *dev,
jngarlitos 1:cab5535713ee 123 enum ltc26x6_write_command write_command, uint16_t dac_code)
jngarlitos 1:cab5535713ee 124 {
jngarlitos 1:cab5535713ee 125 uint8_t data[3];
jngarlitos 1:cab5535713ee 126
jngarlitos 1:cab5535713ee 127 data[0] = write_command; // Write command
jngarlitos 1:cab5535713ee 128 data[1] = dac_code >>8; // MSB code
jngarlitos 1:cab5535713ee 129 data[2] = dac_code & 0x00FF; // LSB code
jngarlitos 1:cab5535713ee 130
jngarlitos 1:cab5535713ee 131 return(i2c_write(dev->i2c_desc, data, 3, 1));
jngarlitos 1:cab5535713ee 132 }
jngarlitos 1:cab5535713ee 133
jngarlitos 1:cab5535713ee 134 /**
jngarlitos 1:cab5535713ee 135 * Power down the device
jngarlitos 1:cab5535713ee 136 * @param device - The device structure.
jngarlitos 1:cab5535713ee 137 * @return 0 in case of success, negative error code otherwise.
jngarlitos 1:cab5535713ee 138 */
jngarlitos 1:cab5535713ee 139 int32_t ltc26x6_power_down(struct ltc26x6_dev *dev)
jngarlitos 1:cab5535713ee 140 {
jngarlitos 1:cab5535713ee 141 uint8_t command = LTC26X6_POWER_DOWN_COMMAND;
jngarlitos 1:cab5535713ee 142 return (i2c_write(dev->i2c_desc, &command, 1, 1));
jngarlitos 1:cab5535713ee 143 }
jngarlitos 1:cab5535713ee 144
jngarlitos 1:cab5535713ee 145 /**
jngarlitos 1:cab5535713ee 146 * Power up the device
jngarlitos 1:cab5535713ee 147 * @param device - The device structure.
jngarlitos 1:cab5535713ee 148 * @return 0 in case of success, negative error code otherwise.
jngarlitos 1:cab5535713ee 149 */
jngarlitos 1:cab5535713ee 150 int32_t ltc26x6_power_up(struct ltc26x6_dev *dev)
jngarlitos 1:cab5535713ee 151 {
jngarlitos 1:cab5535713ee 152 uint8_t command = LTC26X6_UPDATE_COMMAND;
jngarlitos 1:cab5535713ee 153 return (i2c_write(dev->i2c_desc, &command, 1, 1));
jngarlitos 1:cab5535713ee 154 }
jngarlitos 1:cab5535713ee 155