Diff: Accelerometer.cpp

Revision:

7:604a8369b801

Parent:

6:c12cea26842d

Child:

8:cba37530d480

--- a/Accelerometer.cpp	Thu Feb 12 19:00:28 2015 +0000
+++ b/Accelerometer.cpp	Tue Feb 17 16:53:50 2015 +0000
@@ -2,26 +2,69 @@
 #define DEBUG "BMX055-Acc"
 #include "Logger.h"
 
-Accelerometer::Accelerometer(I2C &i2c) : I2CPeripheral(i2c, 0x18 << 1 /* address */) {
-    powerOn();
-    const uint8_t chip_id = read_reg(0x00);
-    if (chip_id == 0xfa) {
+Accelerometer::Accelerometer(I2C &i2c) : I2CPeripheral(i2c, 0x18 << 1 /* address */)
+{
+    if (powerOn()) {
         INFO("Bosch Sensortec BMX055-Accel found");
-        deepSuspend();
+        powerOff();
     } else {
-        WARN("Bosch Sensortec BMX055-Accel not found (chip ID=0x%02x, expected=0x58)", chip_id);
+        WARN("Bosch Sensortec BMX055-Accel not found");
     }
 }
 
-void Accelerometer::powerOn() {
+bool Accelerometer::powerOn()
+{
     write_reg(0x14, 0xB6); // reset
     wait_ms(2); // page 11 says only 1.3ms, nothing for startup time, so assuming 2ms
     write_reg(0x11, 0); // set power normal mode
-    write_reg(0x10, 8); // set bandwidth = 7.81 Hz
-    LOG("powered on");
+    write_reg(0x10, 15); // set bandwidth = 250 Hz
+    return read_reg(0x00) == 0xfa; // verify chip ID
 }
 
-void Accelerometer::deepSuspend() {
+void Accelerometer::powerOff()
+{
     write_reg(0x11, 1); // deep suspend mode
     LOG("deep sleep");
 }
+
+void Accelerometer::start()
+{
+    // nothing to do right now except reset the timestamp counter
+    timer.stop();
+    timer.reset();
+    timer.start();
+}
+
+void Accelerometer::stop()
+{
+    // nothing to do right now
+    timer.stop();
+}
+
+Sensor::Data Accelerometer::read()
+{
+    Sensor::Data frame;
+    
+    // Check comments in the read() function of the Gyroscope for more info why we read bytes one by one.
+    union {
+        uint8_t bytes[6];
+        struct {
+            int16_t x;
+            int16_t y;
+            int16_t z;
+        } values;
+    } f;
+    
+    f.bytes[0] = read_reg(0x02) >> 4;
+    f.bytes[1] = read_reg(0x03);
+    f.bytes[2] = read_reg(0x04) >> 4;
+    f.bytes[3] = read_reg(0x05);
+    f.bytes[4] = read_reg(0x06) >> 4;
+    f.bytes[5] = read_reg(0x07);
+    
+    frame.x = f.values.x;
+    frame.y = f.values.y;
+    frame.z = f.values.z;
+
+    return frame;
+}