2 * Author: Yevgeniy Kiveisha <yevgeniy.kiveisha@intel.com>
3 * Copyright (c) 2014 Intel Corporation.
5 * Permission is hereby granted, free of charge, to any person obtaining
6 * a copy of this software and associated documentation files (the
7 * "Software"), to deal in the Software without restriction, including
8 * without limitation the rights to use, copy, modify, merge, publish,
9 * distribute, sublicense, and/or sell copies of the Software, and to
10 * permit persons to whom the Software is furnished to do so, subject to
11 * the following conditions:
13 * The above copyright notice and this permission notice shall be
14 * included in all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
33 struct MAX31723Exception : public std::exception {
35 MAX31723Exception (std::string msg) : message (msg) { }
36 ~MAX31723Exception () throw () { }
37 const char* what() const throw () { return message.c_str(); }
40 MAX31723::MAX31723 (int csn) {
41 mraa_result_t error = MRAA_SUCCESS;
44 m_csnPinCtx = mraa_gpio_init (csn);
45 if (m_csnPinCtx == NULL) {
46 throw MAX31723Exception ("GPIO failed to initilize");
49 error = mraa_gpio_dir (m_csnPinCtx, MRAA_GPIO_OUT);
50 if (error != MRAA_SUCCESS) {
51 throw MAX31723Exception ("GPIO failed to initilize");
56 m_spi = mraa_spi_init (0);
58 throw MAX31723Exception ("SPI failed to initilize");
61 // set spi mode to mode2 (CPOL = 1, CPHA = 0)
62 mraa_spi_mode (m_spi, MRAA_SPI_MODE2);
63 // set ontinuously perform temperature conversions
64 writeRegister (R_STS_WRITE_CMD, B_CONT_READING);
67 MAX31723::~MAX31723() {
68 mraa_result_t error = MRAA_SUCCESS;
70 error = mraa_spi_stop(m_spi);
71 if (error != MRAA_SUCCESS) {
72 mraa_result_print(error);
74 error = mraa_gpio_close (m_csnPinCtx);
75 if (error != MRAA_SUCCESS) {
76 mraa_result_print(error);
81 MAX31723::getTemperature () {
84 short temperature = 0;
86 lsb = readRegister (R_TEMPERATURE_LSB);
87 msb = readRegister (R_TEMPERATURE_MSB);
89 if ((msb & 0x80) != 0) {
91 temperature = 0 - msb;
107 MAX31723::readRegister (uint8_t reg) {
108 uint8_t data[2] = { 0x00, 0x00 };
109 uint8_t* sensorData = NULL;
113 sensorData = mraa_spi_write_buf(m_spi, data, 2);
116 return sensorData[1];
120 MAX31723::writeRegister (uint8_t reg, uint8_t data) {
121 uint8_t buffer[2] = { 0x00, 0x00 };
122 uint8_t* sensorData = NULL;
127 sensorData = mraa_spi_write_buf(m_spi, buffer, 2);
133 return mraa_gpio_write (m_csnPinCtx, HIGH);
138 return mraa_gpio_write (m_csnPinCtx, LOW);