Diff: max31875.cpp

Revision:

0:f51465145906

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/max31875.cpp	Sun Feb 03 23:50:17 2019 +0000
@@ -0,0 +1,174 @@
+/*******************************************************************************
+* Copyright (C) 2019 Maxim Integrated Products, Inc., All Rights Reserved.
+*
+* Permission is hereby granted, free of charge, to any person obtaining a
+* copy of this software and associated documentation files (the "Software"),
+* to deal in the Software without restriction, including without limitation
+* the rights to use, copy, modify, merge, publish, distribute, sublicense,
+* and/or sell copies of the Software, and to permit persons to whom the
+* Software is furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included
+* in all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES
+* OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+* OTHER DEALINGS IN THE SOFTWARE.
+*
+* Except as contained in this notice, the name of Maxim Integrated
+* Products, Inc. shall not be used except as stated in the Maxim Integrated
+* Products, Inc. Branding Policy.
+*
+* The mere transfer of this software does not imply any licenses
+* of trade secrets, proprietary technology, copyrights, patents,
+* trademarks, maskwork rights, or any other form of intellectual
+* property whatsoever. Maxim Integrated Products, Inc. retains all
+* ownership rights.
+*******************************************************************************
+*/
+#include "max31875.h"
+#include "mbed.h" 
+// #include "USBSerial.h"
+
+
+/******************************************************************************/
+MAX31875::MAX31875(I2C &i2c_bus, uint8_t slaveAddress):
+m_i2c(i2c_bus), 
+m_writeAddress(slaveAddress <<1),
+m_readAddress ((slaveAddress << 1) | 1),
+m_extended_format(0)
+{
+}
+ 
+ 
+/******************************************************************************/
+MAX31875::~MAX31875(void) 
+{
+  /** empty block */
+}
+ 
+
+/******************************************************************************/
+int MAX31875::read_reg(uint16_t *value, char reg) 
+{
+    int32_t ret;
+    char data[2] = {0, 0};
+    max31875_raw_data tmp;
+     
+    if (reg <= MAX31875_REG_MAX) {
+        /* write to the Register Select */
+        ret = m_i2c.write(m_writeAddress, &reg, 1, true);
+        /* read the two bytes of data */
+        if (ret == 0) {
+            ret = m_i2c.read(m_readAddress, data, 2, false);
+            if (ret == 0) {
+                tmp.msb = data[0];  /* MSB */
+                tmp.lsb = data[1];  /* LSB */
+                *value = tmp.swrd;
+                return MAX31875_NO_ERROR;
+            } else {
+                printf(
+                    "%s: failed to read data: ret: %d\r\n", __func__, ret);
+            }
+        } else {                
+            printf("%s: failed to write to Register Select: ret: %d\r\n",
+                __func__, ret);
+        }
+    } else {
+        printf("%s: register address is not correct: register: %d\r\n",
+                __func__, reg);
+    }                
+    return MAX31875_ERROR;
+}
+
+
+float MAX31875::read_reg_as_temperature(uint8_t reg)
+{
+    max31875_raw_data tmp;
+    float temperature;
+    if (reg == MAX31875_REG_TEMPERATURE ||
+        reg == MAX31875_REG_THYST || reg == MAX31875_REG_TOS) {
+        read_reg(&tmp.uwrd, reg);
+        temperature = (float)tmp.swrd;
+        if (m_extended_format)
+            temperature *= MAX31875_CF_EXTENDED_FORMAT;
+        else
+            temperature *= MAX31875_CF_NORMAL_FORMAT;
+        return temperature;
+    } else {
+        printf("%s: register is invalid, %d r\n", __func__, reg);
+        return 0;
+    }
+}
+
+
+/******************************************************************************/
+int MAX31875::write_reg(uint16_t value, char reg) 
+{
+    int32_t ret;
+    char cmd[3];
+    max31875_raw_data tmp;
+
+    if (reg >= MAX31875_REG_CONFIGURATION && reg <= MAX31875_REG_MAX) {
+        cmd[0] = reg;
+        tmp.uwrd = value;
+        cmd[1] = tmp.msb;
+        cmd[2] = tmp.lsb;
+        ret = m_i2c.write(m_writeAddress, cmd, 3, false);
+        if (ret == 0) {
+            if (tmp.uwrd & MAX31875_CFG_EXTENDED_FORMAT)
+                m_extended_format = 1;
+            else 
+                m_extended_format = 0;
+            return MAX31875_NO_ERROR;
+        } else {
+            printf("%s: I2C write error %d\r\n",__func__, ret);
+            return MAX31875_ERROR;
+        }
+    } else {
+        printf("%s: register value invalid %x\r\n",__func__, reg);
+        return MAX31875_ERROR;
+    }
+}
+
+
+int MAX31875::write_cfg(uint16_t cfg)
+{
+    return write_reg(cfg, MAX31875_REG_CONFIGURATION);
+}
+
+
+int MAX31875::write_trip_low(float temperature)
+{
+    max31875_raw_data raw;
+    if (m_extended_format)
+        temperature /= MAX31875_CF_EXTENDED_FORMAT;
+    else
+        temperature /= MAX31875_CF_NORMAL_FORMAT;
+    raw.uwrd = uint16_t(temperature);
+    return write_reg(raw.uwrd, MAX31875_REG_THYST);
+}
+
+
+int MAX31875::write_trip_high(float temperature)
+{
+    max31875_raw_data raw;
+    if (m_extended_format)
+        temperature /= MAX31875_CF_EXTENDED_FORMAT;
+    else
+        temperature /= MAX31875_CF_NORMAL_FORMAT;
+    raw.uwrd = uint16_t(temperature);
+    return write_reg(raw.uwrd, MAX31875_REG_TOS);
+}
+
+
+float MAX31875::celsius_to_fahrenheit(float temp_c)
+{
+    float temp_f;
+    temp_f = ((temp_c * 9)/5) + 32;
+    return temp_f;
+}
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