Make device address configurable

The i2c address can be changed by pulling the AD0 pin up (Section 6.4,
Page 15 of datasheet revision 3.2).

This can be necessary to do if there is an address conflict with
another chip.

src/device.rs

@@ -57,7 +57,7 @@ pub const ACC_REGZ_H : u8= 0x3f;
 /// High Byte Register Temperature
 pub const TEMP_OUT_H : u8= 0x41;
 /// Slave address of Mpu6050
-pub const SLAVE_ADDR: u8 = 0x68;
+pub const DEFAULT_SLAVE_ADDR: u8 = 0x68;
 /// Internal register to check slave addr
 pub const WHOAMI: u8 = 0x75;
 

src/lib.rs

@@ -76,6 +76,7 @@ pub enum Mpu6050Error<E> {
 /// Handles all operations on/with Mpu6050
 pub struct Mpu6050<I> {
     i2c: I,
+    slave_addr: u8,
     acc_sensitivity: f32,
     gyro_sensitivity: f32,
 }
@@ -88,8 +89,9 @@ where
     pub fn new(i2c: I) -> Self {
         Mpu6050 {
             i2c,
+            slave_addr: DEFAULT_SLAVE_ADDR,
             acc_sensitivity: ACCEL_SENS.0,
-            gyro_sensitivity: GYRO_SENS.0, 
+            gyro_sensitivity: GYRO_SENS.0,
         }
     }
 
@@ -97,6 +99,27 @@ where
     pub fn new_with_sens(i2c: I, arange: AccelRange, grange: GyroRange) -> Self {
         Mpu6050 {
             i2c,
+            slave_addr: DEFAULT_SLAVE_ADDR,
+            acc_sensitivity: arange.sensitivity(),
+            gyro_sensitivity: grange.sensitivity(),
+        }
+    }
+
+    /// Same as `new`, but the chip address can be specified (e.g. 0x69, if the A0 pin is pulled up)
+    pub fn new_with_addr(i2c: I, slave_addr: u8) -> Self {
+        Mpu6050 {
+            i2c,
+            slave_addr,
+            acc_sensitivity: ACCEL_SENS.0,
+            gyro_sensitivity: GYRO_SENS.0,
+        }
+    }
+
+    /// Combination of `new_with_sens` and `new_with_addr`
+    pub fn new_with_addr_and_sens(i2c: I, slave_addr: u8, arange: AccelRange, grange: GyroRange) -> Self {
+        Mpu6050 {
+            i2c,
+            slave_addr,
             acc_sensitivity: arange.sensitivity(),
             gyro_sensitivity: grange.sensitivity(),
         }
@@ -143,7 +166,7 @@ where
     /// Verifies device to address 0x68 with WHOAMI.addr() Register
     fn verify(&mut self) -> Result<(), Mpu6050Error<E>> {
         let address = self.read_byte(WHOAMI)?;
-        if address != SLAVE_ADDR {
+        if address != DEFAULT_SLAVE_ADDR {
             return Err(Mpu6050Error::InvalidChipId(address));
         }
         Ok(())
@@ -358,7 +381,7 @@ where
 
     /// Writes byte to register
     pub fn write_byte(&mut self, reg: u8, byte: u8) -> Result<(), Mpu6050Error<E>> {
-        self.i2c.write(SLAVE_ADDR, &[reg, byte])
+        self.i2c.write(self.slave_addr, &[reg, byte])
             .map_err(Mpu6050Error::I2c)?;
         // delay disabled for dev build
         // TODO: check effects with physical unit
@@ -399,14 +422,14 @@ where
     /// Reads byte from register
     pub fn read_byte(&mut self, reg: u8) -> Result<u8, Mpu6050Error<E>> {
         let mut byte: [u8; 1] = [0; 1];
-        self.i2c.write_read(SLAVE_ADDR, &[reg], &mut byte)
+        self.i2c.write_read(self.slave_addr, &[reg], &mut byte)
             .map_err(Mpu6050Error::I2c)?;
         Ok(byte[0])
     }
 
     /// Reads series of bytes into buf from specified reg
     pub fn read_bytes(&mut self, reg: u8, buf: &mut [u8]) -> Result<(), Mpu6050Error<E>> {
-        self.i2c.write_read(SLAVE_ADDR, &[reg], buf)
+        self.i2c.write_read(self.slave_addr, &[reg], buf)
             .map_err(Mpu6050Error::I2c)?;
         Ok(())
     }