Richard Parker
HMC6352 Library
Diff: HMC6352.cpp
- Revision:
- 0:78e66010e47b
- Child:
- 1:1f500fa755c8
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/HMC6352.cpp Thu Feb 11 12:18:33 2010 +0000
@@ -0,0 +1,317 @@
+// Copyright 2009 Richard Parker
+
+#include "mbed.h"
+#include "HMC6352.h"
+
+// Misc defines.
+#define HMC6352_DEFAULT_ADDRESS 0x42
+
+// Masks.
+#define HMC6352_OP_MODE_MASK 0x03
+#define HMC6352_OP_FREQ_MASK 0x60
+#define HMC6352_OP_AUTO_MASK 0x10
+
+// Register addresses.
+#define HMC6352_ADDRESS_ADDRESS 0x00
+#define HMC6352_XO_MSB_ADDRESS 0x01
+#define HMC6352_XO_LSB_ADDRESS 0x02
+#define HMC6352_YO_MSB_ADDRESS 0x03
+#define HMC6352_YO_LSB_ADDRESS 0x04
+#define HMC6352_TIME_DELAY_ADDRESS 0x05
+#define HMC6352_SUMMING_ADDRESS 0x06
+#define HMC6352_VERSION_ADDRESS 0x07
+#define HMC6352_OPERATION_ADDRESS 0x08
+
+#define HMC6352_OUTPUT_REGISTER 0x4E
+#define HMC6352_OPERATION_REGISTER 0x74
+
+// Commands for HMC6352.
+#define HMC6352_WRITE_EEPROM 0x77 // 'w'
+#define HMC6352_READ_EEPROM 0x72 // 'r'
+#define HMC6352_WRITE_RAM 0x47 // 'G'
+#define HMC6352_READ_RAM 0x67 // 'g'
+#define HMC6352_WAKE_UP 0x57 // 'W'
+#define HMC6352_SLEEP 0x53 // 'S'
+#define HMC6352_RESET 0x4F // 'O'
+#define HMC6352_START_CAL 0x43 // 'C'
+#define HMC6352_END_CAL 0x45 // 'E'
+#define HMC6352_SAVE_OPERATION 0x4C // 'L'
+#define HMC6352_RETRIEVE_HEADING 0x41 // 'A'
+
+HMC6352::HMC6352(PinName sda, PinName scl)
+: _i2c(sda, scl),
+ _address(HMC6352_DEFAULT_ADDRESS)
+{
+ // Set the frequency of the transfers in Hz for HMC6352 is 100000 Hz.
+ _i2c.frequency(100000);
+}
+
+HMC6352::~HMC6352()
+{
+}
+
+char HMC6352::getVersion()
+{
+ // Read the version number of the chip will be above 0x00 if it
+ // is a production chip.
+ _readFromMemory(HMC6352_VERSION_ADDRESS, true);
+ return _buffer[0];
+}
+
+void HMC6352::setVersion(const char version)
+{
+ // Write the version number to the chip.
+ _writeToMemory(HMC6352_VERSION_ADDRESS, version, true);
+}
+
+char HMC6352::getTimeDelay()
+{
+ // Read the time delay
+ _readFromMemory(HMC6352_TIME_DELAY_ADDRESS, true);
+ return _buffer[0];
+}
+
+void HMC6352::setTimeDelay(const char delay)
+{
+ // Write the time delay to the chip.
+ _writeToMemory(HMC6352_TIME_DELAY_ADDRESS, delay, true);
+}
+
+char HMC6352::getSumming()
+{
+ // Read the number of summing samples.
+ _readFromMemory(HMC6352_SUMMING_ADDRESS, true);
+ return _buffer[0];
+}
+
+void HMC6352::setSumming(const char samples)
+{
+ // Write the number of summing samples to the chip.
+ _writeToMemory(HMC6352_SUMMING_ADDRESS, samples, true);
+}
+
+float HMC6352::getHeading()
+{
+ // Send the retrieve heading command.
+ _buffer[0] = HMC6352_RETRIEVE_HEADING;
+ _i2c.write(this->address(), _buffer, 1);
+ // Retrieve takes 6000us.
+ wait_us(6000);
+
+ // As soon as the rerieve command has been sent read the result read
+ // commands only return 2 bytes.
+ _clearBuffer();
+ _i2c.read(this->address(), _buffer, 2);
+
+ return _bufferToHeading();
+}
+
+HMC6352::Mode HMC6352::getMode()
+{
+ // Read the operation mode.
+ _readFromMemory(HMC6352_OPERATION_REGISTER, false);
+
+ // Buffer now contains the op mode register, mask to get values.
+ int opmode = _buffer[0];
+ opmode = opmode & HMC6352_OP_MODE_MASK;
+
+ // Convert the value into the mode.
+ switch (opmode)
+ {
+ case 0x0:
+ return HMC6352::Standby;
+ case 0x1:
+ return HMC6352::Query;
+ case 0x2:
+ return HMC6352::Continuous;
+ default:
+ return HMC6352::None;
+ }
+}
+
+void HMC6352::setMode(HMC6352::Mode mode)
+{
+ _readFromMemory(HMC6352_OPERATION_REGISTER, false);
+
+ switch (mode)
+ {
+ case HMC6352::Standby:
+ _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x0, false);
+ break;
+ case HMC6352::Query:
+ _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x1, false);
+ break;
+ case HMC6352::Continuous:
+ _writeToMemory(HMC6352_OPERATION_REGISTER, (_buffer[0] & 0xFC) | 0x2, false);
+ break;
+ default:
+ return;
+ }
+}
+
+HMC6352::Output HMC6352::getOutput()
+{
+ // Read the output mode from RAM
+ _readFromMemory(HMC6352_OUTPUT_REGISTER, false);
+
+ // Buffer now contains the output register.
+ int output = _buffer[0];
+
+ // Convert the value into the mode.
+ switch (output)
+ {
+ case 0x0:
+ return HMC6352::Heading;
+ case 0x1:
+ return HMC6352::RawX;
+ case 0x2:
+ return HMC6352::RawY;
+ case 0x3:
+ return HMC6352::X;
+ case 0x4:
+ return HMC6352::Y;
+ default:
+ return HMC6352::Unknown;
+ }
+}
+
+void HMC6352::setOutput(HMC6352::Output output)
+{
+ switch (output)
+ {
+ case HMC6352::Heading:
+ _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x0, false);
+ break;
+ case HMC6352::RawX:
+ _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x1, false);
+ break;
+ case HMC6352::RawY:
+ _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x2, false);
+ break;
+ case HMC6352::X:
+ _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x3, false);
+ break;
+ case HMC6352::Y:
+ _writeToMemory(HMC6352_OUTPUT_REGISTER, 0x4, false);
+ break;
+ default:
+ return;
+ }
+}
+
+void HMC6352::calibrate(int delay)
+{
+ // Send the enter calibrate command.
+ _buffer[0] = HMC6352_START_CAL;
+ _i2c.write(this->address(), _buffer, 1);
+ // Enter takes 10us.
+ wait_us(10);
+
+ // Now wait an optimal 20s in which two full turns should be
+ // made of the compass to gather enough data, see page 7 of
+ // the data sheet.
+ wait(delay);
+
+ // Send the exit calibrate command.
+ _buffer[0] = HMC6352_END_CAL;
+ _i2c.write(this->address(), _buffer, 1);
+ // Enter takes 14000us.
+ wait_us(14000);
+}
+
+void HMC6352::saveOperation()
+{
+ // Send the enter calibrate command.
+ _buffer[0] = HMC6352_SAVE_OPERATION;
+ _i2c.write(this->address(), _buffer, 1);
+ // Save takes 125us.
+ wait_us(125);
+}
+
+void HMC6352::reset()
+{
+ // Send the reset command.
+ _buffer[0] = HMC6352_RESET;
+ _i2c.write(this->address(), _buffer, 1);
+ // Reset takes 6000us.
+ wait_us(6000);
+}
+
+void HMC6352::wakeUp()
+{
+ // Send the wakeup command.
+ _buffer[0] = HMC6352_WAKE_UP;
+ _i2c.write(this->address(), _buffer, 1);
+ wait_us(100);
+}
+
+void HMC6352::goToSleep()
+{
+ // Send the reset command.
+ _buffer[0] = HMC6352_SLEEP;
+ _i2c.write(this->address(), _buffer, 1);
+ wait_us(10);
+}
+
+void HMC6352::_readFromMemory(const char address, const bool eeprom)
+{
+ char command;
+
+ // Decide what the command should be (either read from eeprom or
+ // currently loaded memory).
+ if (eeprom == true)
+ {
+ command = HMC6352_READ_EEPROM;
+ } else {
+ command = HMC6352_READ_RAM;
+ }
+
+ // Send the read command to the current address (commands are always
+ // two bytes long).
+ _buffer[0] = command;
+ _buffer[1] = address;
+ _i2c.write(this->address(), _buffer, 2);
+ wait_us(70);
+
+ // As soon as the read command has been sent read the result read
+ // commands only return 1 byte.
+ _clearBuffer();
+ _i2c.read(this->address(), _buffer, 1);
+}
+
+void HMC6352::_writeToMemory(const char address, const char data, const bool eeprom)
+{
+ char command;
+
+ // Decide what the command should be (either write to eeprom or
+ // currently loaded memory).
+ if (eeprom == true)
+ {
+ command = HMC6352_WRITE_EEPROM;
+ } else {
+ command = HMC6352_WRITE_RAM;
+ }
+
+ // Send the write data to the current address (commands are always
+ // three bytes long).
+ _buffer[0] = command;
+ _buffer[1] = address;
+ _buffer[2] = data;
+ _i2c.write(this->address(), _buffer, 3);
+ wait_us(70);
+}
+
+void HMC6352::_clearBuffer()
+{
+ // Set both buffer bytes to null.
+ _buffer[0] = 0x0;
+ _buffer[1] = 0x0;
+ _buffer[2] = 0x0;
+}
+
+float HMC6352::_bufferToHeading()
+{
+ // The heading is returned as a 16 bit number with the msb in the first
+ // byte and the lsb in the next byte.
+ return (((_buffer[0] << 8) + _buffer[1])/10.0);
+}