Diff: SRF08.cpp

Revision:

0:70df4930eee9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SRF08.cpp	Tue Aug 11 13:01:45 2015 +0000
@@ -0,0 +1,150 @@
+/*
+Copyright (c) 2012 Brent Dekker
+ 
+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 THE
+AUTHORS OR COPYRIGHT HOLDERS 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.
+*/
+ 
+#include "SRF08.h"
+ 
+/*
+ * Constructor: SRF08
+ * Args:
+ * Returns:     void
+ * Description: Creates an instance of the SRF08 to communicate with a sRF08 module
+ */
+SRF08::SRF08(PinName SDA, PinName SCL, int i2cAddress) :
+        i2cMod(SDA, SCL), 
+        i2cAddress(i2cAddress),  
+        rangingBusy(false) {
+ 
+}
+ 
+/*
+ * Function:    startRanging
+ * Args:        void
+ * Returns:     void
+ * Description: Sends command to module to start ranging.
+ */
+void SRF08::startRanging() {
+    //Create a two byte command. The first first byte is the register address
+    // on the SRF08 to write to. The second byte is the command which is written
+    // to that address ("Start ranging in cm" in this case).
+    const char command[] = {0x00, 0x51};
+    i2cMod.write(i2cAddress, command, 2);
+    this->rangingBusy = true;
+    Thread::wait(70);
+    setRangingFinished();
+}
+ 
+/*
+ * Function:    rangingFinished
+ * Args:        void
+ * Returns:     Bool: whether ranging is finished
+ * Description: Checks if the ranging process on the module is finished
+ */
+bool SRF08::rangingFinished() {
+    if(this->rangingBusy) return false;
+    return true;
+}
+ 
+/*
+ * Function:    getRange
+ * Args:        void
+ * Returns:     int range
+ * Description: Range in cm. This function should only be called when ranging is finished, otherwise previous value is returned
+ */
+int SRF08::getRange() {
+    while (!rangingFinished() ) 
+        Thread::wait(10);   //Wait until ranging is finished
+    const char command[]  = {0x02};           //Address of range register
+    char response[] = {0x00, 0x00};
+    i2cMod.write(i2cAddress, command, 1, 1);  //Send command
+    i2cMod.read(i2cAddress, response, 2);     //Read 16bits result
+    int range = (response[0]<<8)+response[1]; //Shift two bytes into int
+    return range;                             //Return int range
+}
+ 
+/*
+ * Function:    readLightIntensity
+ * Args:        void
+ * Returns:     int lightIntensity
+ * Description: Reads the lightIntensity from the module
+ *              The light intensity is updated if a range command is sent, so don't use
+ *              this function only
+ */
+int SRF08::getLightIntensity() {
+    const char command[] = {0x01};           //Light intensity register
+    char response[] = {0x00};
+    i2cMod.write(i2cAddress, command, 1, 1); //Send command
+    i2cMod.read(i2cAddress, response, 1);    //Read response
+    int lightIntensity = response[0];
+    return lightIntensity;
+}
+ 
+/*
+ * Function:    setRangeRegister
+ * Args:        rangeVal
+ * Returns:     void
+ * Description: Sets the maximum range for which the module waits for an echo
+ *              The range is ((rangeVal x 43mm) + 43mm)
+ *              The max range is about six meters
+ */
+void SRF08::setRangeRegister(unsigned char rangeVal) {
+    while (!rangingFinished() ) 
+        Thread::wait(10);                    //Wait until ranging is finished
+    char command[] = {0x02, rangeVal};       //Range register
+    i2cMod.write(i2cAddress, command, 2);    //Send command
+}
+ 
+ 
+//Function setMaxGainRegister
+void SRF08::setMaxGainRegister(unsigned char gainVal) {
+    while (!rangingFinished() ) 
+        Thread::wait(10);                    //Wait until ranging is finished
+    char command[] = {0x01, gainVal};        //Max gain register
+    i2cMod.write(i2cAddress, command, 2);    //Send command
+}
+ 
+/*
+ * Function:    setAddress
+ * Args:        address
+ * Returns:     void
+ * Description: Sets the address of the module on the I2C bus. The factory default address is 0x0E (224)
+ *                  The address can have the following values:
+ *                      E0 | E2 | E4 | E6 ... FC | FE
+ */
+void SRF08::setAddress(int address) {
+    //Send address change sequence
+    char command[] = {0x00, 0xA0};
+    i2cMod.write(i2cAddress, command, 2);
+    command[1] = 0xAA;
+    i2cMod.write(i2cAddress, command, 2);
+    command[1] = 0xA5;
+    i2cMod.write(i2cAddress, command, 2);
+    command[1] = address;
+    i2cMod.write(i2cAddress, command, 2);
+    //Save the updated address
+    i2cAddress = address;
+}
+ 
+//Small helper function for Timeout object
+void SRF08::setRangingFinished() {
+    this->rangingBusy = false;
+}
+            
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