Diff: LM75B/LM75B.cpp

Revision:

6:37b6d0d56190

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LM75B/LM75B.cpp	Wed Aug 20 12:45:14 2014 +0000
@@ -0,0 +1,286 @@
+/* LM75B Driver Library
+ * Copyright (c) 2013 Neil Thiessen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "LM75B.h"
+
+LM75B::LM75B(PinName sda, PinName scl, Address addr, int hz) : m_I2C(sda, scl), m_ADDR((int)addr)
+{
+    //Set the I2C bus frequency
+    m_I2C.frequency(hz);
+}
+
+bool LM75B::open()
+{
+    //Probe for the LM75B using a Zero Length Transfer
+    if (!m_I2C.write(m_ADDR, NULL, 0)) {
+        //Return success
+        return true;
+    } else {
+        //Return failure
+        return false;
+    }
+}
+
+LM75B::PowerMode LM75B::powerMode()
+{
+    //Read the 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Return the status of the SHUTDOWN bit
+    if (value & (1 << 0))
+        return POWER_SHUTDOWN;
+    else
+        return POWER_NORMAL;
+}
+
+void LM75B::powerMode(PowerMode mode)
+{
+    //Read the current 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Set or clear the SHUTDOWN bit
+    if (mode == POWER_SHUTDOWN)
+        value |= (1 << 0);
+    else
+        value &= ~(1 << 0);
+
+    //Write the value back out
+    write8(REG_CONF, value);
+}
+
+LM75B::OSMode LM75B::osMode()
+{
+    //Read the 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Return the status of the OS_COMP_INT bit
+    if (value & (1 << 1))
+        return OS_INTERRUPT;
+    else
+        return OS_COMPARATOR;
+}
+
+void LM75B::osMode(OSMode mode)
+{
+    //Read the current 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Set or clear the OS_COMP_INT bit
+    if (mode == OS_INTERRUPT)
+        value |= (1 << 1);
+    else
+        value &= ~(1 << 1);
+
+    //Write the value back out
+    write8(REG_CONF, value);
+}
+
+LM75B::OSPolarity LM75B::osPolarity()
+{
+    //Read the 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Return the status of the OS_POL bit
+    if (value & (1 << 2))
+        return OS_ACTIVE_HIGH;
+    else
+        return OS_ACTIVE_LOW;
+}
+
+void LM75B::osPolarity(OSPolarity polarity)
+{
+    //Read the current 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Set or clear the OS_POL bit
+    if (polarity == OS_ACTIVE_HIGH)
+        value |= (1 << 2);
+    else
+        value &= ~(1 << 2);
+
+    //Write the value back out
+    write8(REG_CONF, value);
+}
+
+LM75B::OSFaultQueue LM75B::osFaultQueue()
+{
+    //Read the 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Return the status of the OS_F_QUE bits
+    if ((value & (1 << 3)) && (value & (1 << 4)))
+        return OS_FAULT_QUEUE_6;
+    else if (!(value & (1 << 3)) && (value & (1 << 4)))
+        return OS_FAULT_QUEUE_4;
+    else if ((value & (1 << 3)) && !(value & (1 << 4)))
+        return OS_FAULT_QUEUE_2;
+    else
+        return OS_FAULT_QUEUE_1;
+}
+
+void LM75B::osFaultQueue(OSFaultQueue queue)
+{
+    //Read the current 8-bit register value
+    char value = read8(REG_CONF);
+
+    //Clear the old OS_F_QUE bits
+    value &= ~(3 << 3);
+
+    //Set the new OS_F_QUE bits
+    if (queue == OS_FAULT_QUEUE_2)
+        value |= (1 << 3);
+    else if (queue == OS_FAULT_QUEUE_4)
+        value |= (2 << 3);
+    else if (queue == OS_FAULT_QUEUE_6)
+        value |= (3 << 3);
+
+    //Write the value back out
+    write8(REG_CONF, value);
+}
+
+float LM75B::alertTemp()
+{
+    //Use the 9-bit helper to read the TOS register
+    return readAlertTempHelper(REG_TOS);
+}
+
+void LM75B::alertTemp(float temp)
+{
+    //Use the 9-bit helper to write to the TOS register
+    return writeAlertTempHelper(REG_TOS, temp);
+}
+
+float LM75B::alertHyst()
+{
+    //Use the 9-bit helper to read the THYST register
+    return readAlertTempHelper(REG_THYST);
+}
+
+void LM75B::alertHyst(float temp)
+{
+    //Use the 9-bit helper to write to the THYST register
+    return writeAlertTempHelper(REG_THYST, temp);
+}
+
+float LM75B::temp()
+{
+    //Signed return value
+    short value;
+
+    //Read the 11-bit raw temperature value
+    value = read16(REG_TEMP) >> 5;
+
+    //Sign extend negative numbers
+    if (value & (1 << 10))
+        value |= 0xFC00;
+
+    //Return the temperature in °C
+    return value * 0.125;
+}
+
+#ifdef MBED_OPERATORS
+LM75B::operator float()
+{
+    //Return the current temperature reading
+    return temp();
+}
+#endif
+
+char LM75B::read8(char reg)
+{
+    //Select the register
+    m_I2C.write(m_ADDR, &reg, 1, true);
+
+    //Read the 8-bit register
+    m_I2C.read(m_ADDR, &reg, 1);
+
+    //Return the byte
+    return reg;
+}
+
+void LM75B::write8(char reg, char data)
+{
+    //Create a temporary buffer
+    char buff[2];
+
+    //Load the register address and 8-bit data
+    buff[0] = reg;
+    buff[1] = data;
+
+    //Write the data
+    m_I2C.write(m_ADDR, buff, 2);
+}
+
+unsigned short LM75B::read16(char reg)
+{
+    //Create a temporary buffer
+    char buff[2];
+
+    //Select the register
+    m_I2C.write(m_ADDR, &reg, 1, true);
+
+    //Read the 16-bit register
+    m_I2C.read(m_ADDR, buff, 2);
+
+    //Return the combined 16-bit value
+    return (buff[0] << 8) | buff[1];
+}
+
+void LM75B::write16(char reg, unsigned short data)
+{
+    //Create a temporary buffer
+    char buff[3];
+
+    //Load the register address and 16-bit data
+    buff[0] = reg;
+    buff[1] = data >> 8;
+    buff[2] = data;
+
+    //Write the data
+    m_I2C.write(m_ADDR, buff, 3);
+}
+
+float LM75B::readAlertTempHelper(char reg)
+{
+    //Signed return value
+    short value;
+
+    //Read the 9-bit raw temperature value
+    value = read16(reg) >> 7;
+
+    //Sign extend negative numbers
+    if (value & (1 << 8))
+        value |= 0xFF00;
+
+    //Return the temperature in °C
+    return value * 0.5;
+}
+
+void LM75B::writeAlertTempHelper(char reg, float temp)
+{
+    //Range limit temp
+    if (temp < -55.0)
+        temp = -55.0;
+    else if (temp > 125.0)
+        temp = 125.0;
+
+    //Extract and shift the signed integer
+    short value = temp * 2;
+    value <<= 7;
+
+    //Send the new value
+    write16(reg, value);
+}