Revision 1:0ab483c143d4, committed 2015-04-29

Comitter:

el14pr

Date:

Wed Apr 29 14:39:56 2015 +0000

Parent:

0:df3b9e41edf3

Child:

2:93e89f3b0649

Commit message:

1

Changed in this revision

--- a/MMA8452.cpp	Sun Mar 08 15:31:02 2015 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,142 +0,0 @@
-/**
-@file MMA8452.cpp
-
-@brief Member functions implementations
-
-*/
-#include "mbed.h"
-#include "MMA8452.h"
-
-MMA8452:: MMA8452(PinName sdaPin, PinName sclPin)
-{
-    i2c = new I2C(sdaPin,sclPin); // create new I2C instance and initialise
-    i2c->frequency(400000);       // I2C Fast Mode - 400kHz
-    leds = new BusOut(LED4,LED3,LED2,LED1);  // for debug
-}
-
-void MMA8452::init()
-{
-
-    i2c->frequency(400000); // set Fast Mode I2C frequency (5.10 datasheet)
-
-    char data = readByteFromRegister(WHO_AM_I);  // p18 datasheet
-    if (data != 0x2A) { // if correct ID not found, hand and flash error message
-        error();
-    }
-
-    // put into STANDBY while configuring
-    data = readByteFromRegister(CTRL_REG1); // get current value of register
-    data &= ~(1<<0); // clear bit 0 (p37 datasheet)
-    sendByteToRegister(data,CTRL_REG1);
-
-    // Set output data rate, default is 800 Hz, will set to 100 Hz (clear b5, set b4/b3 - p37 datasheet)
-    data = readByteFromRegister(CTRL_REG1);
-    data &= ~(1<<5);
-    data |=  (1<<4);
-    data |=  (1<<3);
-    sendByteToRegister(data,CTRL_REG1);
-
-    //// Can also change default 2g range to 4g or 8g (p22 datasheet)
-    data = readByteFromRegister(XYZ_DATA_CFG);
-    data |=  (1<<0); // set bit 0 - 4g range
-    sendByteToRegister(data,XYZ_DATA_CFG);
-
-    // set ACTIVE
-    data = readByteFromRegister(CTRL_REG1);
-    data |= (1<<0);   // set bit 0 in CTRL_REG1
-    sendByteToRegister(data,CTRL_REG1);
-
-}
-
-// read acceleration data from device
-Acceleration MMA8452::readValues()
-{
-    // acceleration data stored in 6 registers (0x01 to 0x06)
-    // device automatically increments register, so can read 6 bytes starting from OUT_X_MSB
-    char data[6];
-    readBytesFromRegister(OUT_X_MSB,6,data);
-
-    char x_MSB = data[0];  // extract MSB and LSBs for x,y,z values
-    char x_LSB = data[1];
-    char y_MSB = data[2];
-    char y_LSB = data[3];
-    char z_MSB = data[4];
-    char z_LSB = data[5];
-
-    // [0:7] of MSB are 8 MSB of 12-bit value , [7:4] of LSB are 4 LSB's of 12-bit value
-    // need to type-cast as numbers are in signed (2's complement) form (p20 datasheet)
-    int x = (int16_t) (x_MSB << 8) | x_LSB;  // combine bytes
-    x >>= 4;  // are left-aligned, so shift 4 places right to right-align
-    int y = (int16_t) (y_MSB << 8) | y_LSB;
-    y >>= 4;
-    int z = (int16_t) (z_MSB << 8) | z_LSB;
-    z >>= 4;
-
-    // sensitivity is 1024 counts/g in 2g mode (pg 9 datasheet)
-    //  "   "          512      "      4g     "
-    //  "   "          256      "      8g     "
-    Acceleration acc;
-    
-    acc.x = x/512.0;
-    acc.y = y/512.0;
-    acc.z = z/512.0;
-    
-    return acc;
-}
-
-// reads a byte from a specific register
-char MMA8452::readByteFromRegister(char reg)
-{
-    int nack = i2c->write(MMA8452_W_ADDRESS,&reg,1,true);  // send the register address to the slave
-    // true as need to send repeated start condition (5.10.1 datasheet)
-    // http://www.i2c-bus.org/repeated-start-condition/
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    char rx;
-    nack = i2c->read(MMA8452_R_ADDRESS,&rx,1);  // read a byte from the register and store in buffer
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    return rx;
-}
-
-// reads a series of bytes, starting from a specific register
-void MMA8452::readBytesFromRegister(char reg,int numberOfBytes,char bytes[])
-{
-
-    int nack = i2c->write(MMA8452_W_ADDRESS,&reg,1,true);  // send the slave write address and the configuration register address
-    // true as need to send repeated start condition (5.10.1 datasheet)
-    // http://www.i2c-bus.org/repeated-start-condition/
-
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-    nack = i2c->read(MMA8452_R_ADDRESS,bytes,numberOfBytes);  // read bytes
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-}
-
-// sends a byte to a specific register
-void MMA8452::sendByteToRegister(char byte,char reg)
-{
-    char data[2];
-    data[0] = reg;
-    data[1] = byte;
-    // send the register address, followed by the data
-    int nack = i2c->write(MMA8452_W_ADDRESS,data,2);
-    if (nack)
-        error();  // if we don't receive acknowledgement, flash error message
-
-}
-
-void MMA8452::error()
-{
-    while(1) {
-        leds->write(15);
-        wait(0.1);
-        leds->write(0);
-        wait(0.1);
-    }
-}
\ No newline at end of file

--- a/MMA8452.h	Sun Mar 08 15:31:02 2015 +0000
+++ b/MMA8452.h	Wed Apr 29 14:39:56 2015 +0000
@@ -1,10 +1,3 @@
-/**
-@file MMA8452.h
-
-@brief Header file containing member functions and variables
-
-*/
-
 #ifndef MMA8452_H
 #define MMA8452_H