Revision 0:9bce98da584b, committed 2017-05-04

Comitter:

stevew817

Date:

Thu May 04 12:15:44 2017 +0000

Commit message:

Initial WIP;

Changed in this revision

diff -r 000000000000 -r 9bce98da584b Si7210.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7210.cpp	Thu May 04 12:15:44 2017 +0000
@@ -0,0 +1,234 @@
+#include "Si7210.h"
+
+#define OTP_BUSY_MASK         1
+#define OTP_READ_EN_MASK      2
+#define NUM_HALL_DEVICES      3
+#define STOP_MASK             2
+#define SLTIMEENA_MASK        1
+#define SW_TAMPER_MASK        0xFC
+#define SL_FAST_MASK          2
+#define SLEEP_MASK            1
+#define ONEBURST_MASK         4
+
+namespace silabs {
+Si7210::Si7210(PinName sda, PinName scl, uint8_t address)
+{
+    _i2c = new I2C(sda, scl);
+    _i2c->frequency(400000);
+    _address = address;
+    _ownI2C = true;
+    
+    // Initialize members
+    _temperatureOffset = 0;
+    _temperatureGain = 0;
+    _rawTemperature = 0;
+    _rawField = 0;
+    _range = RANGE_20mT;
+}
+
+Si7210::Si7210(I2C *i2c_bus, uint8_t address)
+{
+    _i2c = i2c_bus;
+    _address = address;
+    _ownI2C = false;
+    
+    // Initialize members
+    _temperatureOffset = 0;
+    _temperatureGain = 0;
+    _rawTemperature = 0;
+    _rawField = 0;
+    _range = RANGE_20mT;
+}
+
+Si7210::~Si7210()
+{
+    if (_ownI2C) {
+        delete _i2c;
+    }
+}
+
+int Si7210::getTemperature()
+{
+    // we operate on 11 fractional bits.
+    int offset;
+    int64_t temperature;
+    
+    if (_temperatureOffset == 0 &&
+        _temperatureGain == 0) {
+        /* read out compensation values */
+        writeRegister(SI72XX_OTP_ADDR, 0x1DU);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, (uint8_t*)&_temperatureOffset);
+        
+        writeRegister(SI72XX_OTP_ADDR, 0x1EU);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, (uint8_t*)&_temperatureGain);
+    }
+    
+    temperature = ((int64_t)_rawTemperature * (int64_t)_rawTemperature) * (-21) / 10000;
+    temperature += ((1522 * _rawTemperature) / 10);
+    temperature -= 273000;
+    
+    
+    // offset = val@0x1D / 16 = val@0x1D / 2048 * 128
+    offset = (int32_t)_temperatureOffset * 1000 / 16;
+    // gain = 1 + val@0x1E
+    // temperature = raw * gain + offset
+    temperature = temperature + (temperature * _temperatureGain / 2048) + offset;
+    // return temperature
+    return temperature;
+}
+
+/*
+ * Get last measured field strength
+ * return: int32_t = field strength in micro-Tesla.
+ */
+int Si7210::getFieldStrength()
+{   
+    switch(_range) {
+        case RANGE_20mT:
+            return (_rawField / 4) + _rawField; // rawField * 1.25
+        case RANGE_200mT:
+            return (_rawField * 12) + (_rawField / 2); //rawField * 12.5
+        default:
+            return 0;
+    }
+}
+
+/*
+ * Set measurement range.
+ * Return true if successful, false if device is not responding.
+ */
+bool Si7210::setFieldStrength(Si7210_range_t range)
+{
+    _range = range;
+}
+
+/*
+ * Perform measurement of magnetic field.
+ * Return true if new data available
+ */
+bool Si7210::fetchFieldStrength()
+{
+    uint8_t temp = 0x04;
+    readRegister(SI72XX_DSPSIGM, &temp);
+    if(temp & 0x80) {
+        /* Fresh data available */
+        _rawField = 0;
+        _rawField += (temp & 0x7FU) * 256;
+        readRegister(SI72XX_DSPSIGL, &temp);
+        _rawField += temp;
+        _rawField -= 16384U;
+        return true;
+    }
+    return false;
+}
+
+bool Si7210::measureOnce()
+{
+    uint8_t temp;
+    wakeup();
+    readRegister(SI72XX_POWER_CTRL, &temp);
+    temp = (temp & 0xF0) | 0xA; // Stop control loop
+    writeRegister(SI72XX_POWER_CTRL, temp);
+    
+    if (_range == RANGE_200mT) {
+        writeRegister(SI72XX_OTP_ADDR, 0x27U);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A0, temp);
+        writeRegister(SI72XX_OTP_ADDR, 0x28U);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A1, temp);
+        writeRegister(SI72XX_OTP_ADDR, 0x29U);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A2, temp);
+        writeRegister(SI72XX_OTP_ADDR, 0x2AU);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A3, temp);
+        writeRegister(SI72XX_OTP_ADDR, 0x2BU);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A4, temp);
+        writeRegister(SI72XX_OTP_ADDR, 0x2CU);
+        writeRegister(SI72XX_OTP_CTRL, OTP_READ_EN_MASK);
+        readRegister(SI72XX_OTP_DATA, &temp);
+        writeRegister(SI72XX_A5, temp);
+    }
+    
+    writeRegister(SI72XX_CTRL4, 0x44); // Use a burst of 4 samples
+    temp = 0x4;
+    writeRegister(SI72XX_DSPSIGSEL, temp); // Select field strength data
+    
+    readRegister(SI72XX_POWER_CTRL, &temp);
+    temp = (temp & 0xF0) | 0x0C; // Start measurement
+    writeRegister(SI72XX_POWER_CTRL, temp);
+    
+    do {
+        readRegister(SI72XX_POWER_CTRL, &temp);
+    } while ( (temp & 0x80) != 0 );
+    
+    fetchFieldStrength();
+    
+    writeRegister(SI72XX_CTRL4, 0x0); // Don't burst
+    temp = 0x1;
+    writeRegister(SI72XX_DSPSIGSEL, temp); // Select temperature data
+    
+    readRegister(SI72XX_POWER_CTRL, &temp);
+    temp = (temp & 0xF0) | 0x0C; // Start measurement
+    writeRegister(SI72XX_POWER_CTRL, temp);
+    
+    readRegister(SI72XX_DSPSIGM, &temp);
+    _rawTemperature = 0;
+    _rawTemperature += 32 * (temp & 0x7F);
+    readRegister(SI72XX_DSPSIGL, &temp);
+    _rawTemperature += (temp >> 3);
+    
+    sleep();
+    return true;
+}
+
+bool Si7210::check()
+{
+    uint8_t temp;
+    wakeup();
+    readRegister(SI72XX_HREVID, &temp);
+    sleep();
+    
+    return true;
+}
+
+bool Si7210::wakeup()
+{
+    uint8_t temp;
+    if(_i2c->read(_address, (char*)&temp, 1) == 0) return true;
+    return false;
+}
+
+bool Si7210::sleep()
+{
+    uint8_t temp;
+    readRegister(SI72XX_CTRL3, &temp);
+    temp &= 0xFEU; // Clear sltimena
+    writeRegister(SI72XX_CTRL3, temp);
+    readRegister(SI72XX_POWER_CTRL, &temp);
+    temp = (temp & 0xF8U) | 0x01; // clear STOP and set SLEEP
+    return writeRegister(SI72XX_POWER_CTRL, temp);
+}
+
+bool Si7210::readRegister(uint8_t reg, uint8_t *result)
+{
+    _i2c->write(_address, (const char*)&reg, 1, true);
+    return _i2c->read(_address, (char*)result, 1) == 0;
+}
+
+bool Si7210::writeRegister(uint8_t reg, uint8_t data)
+{
+    uint8_t buffer[2] = {reg, data};
+    return _i2c->write(_address, (const char*)buffer, 2) == 0;
+}
+
+} // namespace silabs
\ No newline at end of file

diff -r 000000000000 -r 9bce98da584b Si7210.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Si7210.h	Thu May 04 12:15:44 2017 +0000
@@ -0,0 +1,138 @@
+/***************************************************************************//**
+ * @file Si7210.h
+ * @brief Driver class for the Silicon Labs Si7210 I2C Hall-effect sensor
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2017 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
+ * obligation to support this Software. Silicon Labs is providing the
+ * Software "AS IS", with no express or implied warranties of any kind,
+ * including, but not limited to, any implied warranties of merchantability
+ * or fitness for any particular purpose or warranties against infringement
+ * of any proprietary rights of a third party.
+ *
+ * Silicon Labs will not be liable for any consequential, incidental, or
+ * special damages, or any other relief, or for any claim by any third party,
+ * arising from your use of this Software.
+ *
+ ******************************************************************************/
+#ifndef SI7210_H
+#define SI7210_H
+
+#include "mbed.h"
+
+/* Possible I2C slave addresses */
+#define SI7210_ADDRESS_0    (0x30U << 1)
+#define SI7210_ADDRESS_1    (0x31U << 1)
+#define SI7210_ADDRESS_2    (0x32U << 1)
+#define SI7210_ADDRESS_3    (0x33U << 1)
+
+/* Register addresses */
+#define SI72XX_HREVID       0xC0U
+#define SI72XX_DSPSIGM      0xC1U
+#define SI72XX_DSPSIGL      0xC2U
+#define SI72XX_DSPSIGSEL    0xC3U
+#define SI72XX_POWER_CTRL   0xC4U
+#define SI72XX_ARAUTOINC    0xC5U
+#define SI72XX_CTRL1        0xC6U
+#define SI72XX_CTRL2        0xC7U
+#define SI72XX_SLTIME       0xC8U
+#define SI72XX_CTRL3        0xC9U
+#define SI72XX_A0           0xCAU
+#define SI72XX_A1           0xCBU
+#define SI72XX_A2           0xCCU
+#define SI72XX_CTRL4        0xCDU
+#define SI72XX_A3           0xCEU
+#define SI72XX_A4           0xCFU
+#define SI72XX_A5           0xD0U
+#define SI72XX_OTP_ADDR     0xE1U
+#define SI72XX_OTP_DATA     0xE2U
+#define SI72XX_OTP_CTRL     0xE3U
+#define SI72XX_TM_FG        0xE4U
+
+#define SI72XX_ERROR_BUSY   0xFEU
+#define SI72XX_ERROR_NODATA 0xFDU
+
+/* Possible (bipolar) measurement range settings */
+typedef enum {
+    RANGE_20mT,
+    RANGE_200mT
+} Si7210_range_t;
+
+namespace silabs {
+class Si7210
+{
+public:
+    Si7210(PinName sda, PinName scl, uint8_t address);
+    Si7210(I2C *i2c_bus, uint8_t address = SI7210_ADDRESS_0);
+    ~Si7210();
+    
+    /*
+     * Get last measured temperature data
+     * return: int = temperature in 1/4th degrees centigrade
+     */
+    int getTemperature();
+
+    /*
+     * Get last measured field strength
+     * return: int = field strength in micro-Tesla.
+     */
+    int getFieldStrength();
+    
+    /*
+     * Set measurement range.
+     * Return true if successful, false if device is not responding.
+     */
+    bool setFieldStrength(Si7210_range_t range);
+    
+    /*
+     * Return true if successful, false if device is not responding.
+     */
+    bool fetchFieldStrength();
+    
+    bool measureOnce();
+    
+    /*
+     * Check if the sensor is active and responding.
+     */
+    bool check();
+    
+    /* Read a register from Si7210 */
+    bool readRegister(uint8_t reg, uint8_t *result);
+    bool writeRegister(uint8_t reg, uint8_t data);
+    
+    bool wakeup();
+    bool sleep();
+    
+private:
+    
+    I2C *_i2c;
+    bool _ownI2C;
+    
+    uint8_t  _address;
+    
+    int8_t   _temperatureOffset;
+    int8_t   _temperatureGain;
+    
+    int _rawTemperature;
+    int _rawField;
+    
+    Si7210_range_t _range;
+    
+}; // class Si7210
+
+} // namespace silabs
+
+#endif
\ No newline at end of file