Diff: Sensors/I2C_Sensor.cpp

Revision:

34:3aa1cbcde59d

Child:

36:128c55793728

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Sensors/I2C_Sensor.cpp	Mon Jun 10 13:22:46 2013 +0000
@@ -0,0 +1,54 @@
+#include "I2C_Sensor.h"
+
+// calculate the 8-Bit write/read I2C-Address from the 7-Bit adress of the device
+#define GET_I2C_WRITE_ADDRESS(ADR)  (ADR << 1&0xFE) // ADR & 1111 1110
+#define GET_I2C_READ_ADDRESS(ADR)   (ADR << 1|0x01) // ADR | 0000 0001
+
+I2C_Sensor::I2C_Sensor(PinName sda, PinName scl, char i2c_address) :  i2c(sda, scl), local("local")
+{
+    I2C_Sensor::i2c_address = i2c_address;
+    i2c.frequency(400000); // standard speed
+    //i2c.frequency(1500000); // ultrafast!
+}
+
+void I2C_Sensor::saveCalibrationValues(float values[], int size, char * filename)
+{
+    FILE *fp = fopen(strcat("/local/", filename), "w");
+    for(int i = 0; i < size; i++)
+        fprintf(fp, "%f\r\n", values[i]);
+    fclose(fp);
+}
+
+void I2C_Sensor::loadCalibrationValues(float values[], int size, char * filename)
+{
+    FILE *fp = fopen(strcat("/local/", filename), "r");
+    for(int i = 0; i < size; i++)
+        fscanf(fp, "%f", &values[i]);
+    fclose(fp);
+}
+
+//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+// ATTENTION!!! the I2C option "repeated" = true is important because otherwise interrupts while bus communications cause crashes (see http://www.i2c-bus.org/repeated-start-condition/)
+//--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+
+char I2C_Sensor::readRegister(char reg)
+{
+    char value = 0;
+    
+    i2c.write(i2c_address, &reg, 1, true);
+    i2c.read(i2c_address, &value, 1, true);
+
+    return value;
+}
+
+void I2C_Sensor::writeRegister(char reg, char data)
+{
+    char buffer[2] = {reg, data};
+    i2c.write(i2c_address, buffer, 2, true);
+}
+
+void I2C_Sensor::readMultiRegister(char reg, char* output, int size)
+{
+    i2c.write (i2c_address, &reg, 1, true); // tell register address of the MSB get the sensor to do slave-transmit subaddress updating.
+    i2c.read  (i2c_address, output, size, true); // tell it where to store the data read
+}
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