File content as of revision 3:3d08e2045bde:

/*

Copyright (c) 2012-2014 RedBearLab

Permission is hereby granted, free of charge, to any person obtaining a copy of this software 
and associated documentation files (the "Software"), to deal in the Software without restriction, 
including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, 
and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, 
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR 
PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

*/

#include "mbed.h"
#include "wire.h"

#define BLE_Nano
//#define nRF_51822


#ifdef nRF_51822
#define SCL         28
#define SDA         29
#endif

#ifdef BLE_Nano
#define SCL         8  
#define SDA         10
#endif

#define DEV_ADDR    0xA0
#define ADDR_ONE    0x30
#define ADDR_TWO    0x32
#define AXIS_X      0x00
#define AXIS_Y      0x01
#define AXIS_Z      0x02
#define REG_OUT_X_L 0x28
#define REG_CTRL1   0x20
#define REG_CTRL4   0x23
#define REG_WHOAMI  0x0F
#define RANGE_2G    0x00
#define DEVICE_ID   0x33


#define DATARATE_400HZ          0b0111 // 400Hz 
#define DATARATE_200HZ          0b0110 // 200Hz
#define DATARATE_100HZ          0b0101 // 100Hz
#define DATARATE_50HZ           0b0100 // 50Hz
#define DATARATE_25HZ           0b0011 // 25Hz
#define DATARATE_10HZ           0b0010 // 10Hz
#define DATARATE_1HZ            0b0001 // 1Hz
#define DATARATE_POWERDOWN      0      // Power down
#define DATARATE_LOWPOWER_1K6HZ 0b1000 // Low power mode (1.6KHz)
#define DATARATE_LOWPOWER_5KHZ  0b1001 // Low power mode (5KHz) / Normal power mode (1.25KHz)

Serial pc(USBTX, USBRX);
TwoWire Wire = TwoWire(NRF_TWI0);

void AT24C512_WriteBytes(uint16_t addr, uint8_t *pbuf, uint16_t length, uint16_t i2cAddr)
{
    Wire.beginTransmission(i2cAddr);
    int err = Wire.write( (uint8_t)addr );
    Wire.write(pbuf, length);
    if (err != 0) {
        pc.printf("error on write write! %d\n", err);
    }
    uint8_t err8 = Wire.endTransmission();
    if (err8 != 0) {
        pc.printf("error on write end transmission! %d\n", err8);
    }
}

void AT24C512_ReadBytes(uint16_t addr, uint8_t *pbuf, uint16_t length, uint16_t i2cAddr)
{
    Wire.beginTransmission(i2cAddr);
    int err= Wire.write( (uint8_t)addr );
    if (err != 0) {
        pc.printf("error on read write! %d\n", err);
    }
    uint8_t err8 = Wire.endTransmission();
    if (err8 != 0) {
        pc.printf("error on read end transmission! %d\n", err8);
    }
       
    err8 = Wire.requestFrom(i2cAddr+1, length);
    if (err != 0) {
        pc.printf("error on read request from! %d\n", err8);
    }
    while( Wire.available() > 0 )
    {
        *pbuf = Wire.read();
        pbuf++;
    }
}

//Set the bit at index 'bit' to 'value' on 'input' and return
uint8_t setBit(uint8_t input, uint8_t bit, uint8_t value) {
    uint8_t mask = 1 << bit;
    input &= ~mask;
    if (value == 1) {
        input |= mask;
    }
    return input;
}

uint16_t getAxis(uint16_t axis, uint16_t i2cAddr)
{
    uint8_t base = REG_OUT_X_L + (2 * axis);
    uint8_t* low = new uint8_t[1];
    uint8_t* high = new uint8_t[1];
    AT24C512_ReadBytes(base, low, 1, i2cAddr);
    AT24C512_ReadBytes(base + 1, high, 1, i2cAddr);
    uint16_t res = low[0] | (high[0] << 8);
    return res;
}

void setRange(uint8_t range, uint16_t i2cAddr) {
    uint8_t* val = new uint8_t[1];
    AT24C512_ReadBytes(REG_CTRL4, val, 1, i2cAddr);//get value from the register
    val[0] &= ~(0b110000); //zero out lowest 4 bits
    val[0] |= (range << 4); // write in our new range
    AT24C512_WriteBytes(REG_CTRL4, val, 1, i2cAddr);
}

//Set whether we want to use high resolution or not
void setHighResolution(bool highRes, uint16_t i2cAddr) {
    uint8_t* val = new uint8_t[1];
    AT24C512_ReadBytes(REG_CTRL4, val, 1, i2cAddr);//get value from the register
    uint8_t final;
    if (highRes) {
        final = setBit(val[0], 3, 1);
    } else {
        final = setBit(val[0], 3, 1);
    }
    val[0] = final;
    AT24C512_WriteBytes(REG_CTRL4, val, 1, i2cAddr);
}

void setAxisStatus(uint8_t axis, bool enable, uint16_t i2cAddr) {
    uint8_t* current = new uint8_t[1];
    AT24C512_ReadBytes(REG_CTRL1, current, 1, i2cAddr);//get value from the register
    uint8_t final;
    if (enable == 1) {
        final = setBit(current[0], axis, 1);
    } else {
        final = setBit(current[0], axis, 0);
    }
    current[0] = final;
    AT24C512_WriteBytes(REG_CTRL1, current, 1, i2cAddr);
}

void setDataRate(uint8_t dataRate, uint16_t i2cAddr) {
    uint8_t* val = new uint8_t[1];
    AT24C512_ReadBytes(REG_CTRL1, val, 1, i2cAddr);
    val[0] &= 0b1111; //mask off lower bits
    val[0] |= (dataRate << 4);
    AT24C512_WriteBytes(REG_CTRL1, val, 1, i2cAddr);
}
    
void setBDU(bool bdu, uint16_t i2cAddr)
{
    uint8_t* val = new uint8_t[1];
    AT24C512_ReadBytes(REG_CTRL4, val, 1, i2cAddr);//get value from the register
    uint8_t final;
    if (bdu == true) {
        final = setBit(val[0], 7, 1);
    } else {
        final = setBit(val[0], 7, 1);
    }
    val[0] = final;
    AT24C512_WriteBytes(REG_CTRL4, val, 1, i2cAddr);
}

uint16_t getX(uint16_t i2cAddr)
{
    return getAxis(AXIS_X, i2cAddr);
}

uint16_t getY(uint16_t i2cAddr)
{
    return getAxis(AXIS_Y, i2cAddr); 
}

uint16_t getZ(uint16_t i2cAddr)
{
    return getAxis(AXIS_Z, i2cAddr);
}

int main(void)
{
    pc.baud(9600);
    wait(5);
    //Wire.begin();
    Wire.begin(SCL, SDA, TWI_FREQUENCY_100K);
    pc.printf("IIC Demo Start \r\n");
    
    int nDevices = 0;
    for (int i = 0; i < 128; i++) {
        uint8_t i2caddr = (i << 1);
        Wire.beginTransmission(i2caddr);
        int error = Wire.endTransmission();
        if(error == 0) {
            pc.printf("I2C device found at 0x%x\n", i);
            nDevices++;
        }
    }
    if (nDevices == 0){
        pc.printf("No I2C devices found\n");
    } else
        pc.printf("done\n");
    
    uint8_t* whoami = new uint8_t[1];
    AT24C512_ReadBytes(REG_WHOAMI, whoami, 1, ADDR_ONE);
    pc.printf("Whoami: %d\r\n", whoami[1]);
    
    wait(15);
    
    setAxisStatus(AXIS_X, true, ADDR_ONE);
    setAxisStatus(AXIS_Y, true, ADDR_ONE);
    setAxisStatus(AXIS_Z, true, ADDR_ONE);
    setDataRate(DATARATE_400HZ, ADDR_ONE);
    setHighResolution(true, ADDR_ONE);
    setBDU(true, ADDR_ONE);
    setRange(RANGE_2G, ADDR_ONE);
    
    setAxisStatus(AXIS_X, true, ADDR_TWO);
    setAxisStatus(AXIS_Y, true, ADDR_TWO);
    setAxisStatus(AXIS_Z, true, ADDR_TWO);
    setDataRate(DATARATE_400HZ, ADDR_ONE);
    setHighResolution(true, ADDR_TWO);
    setBDU(true, ADDR_TWO);
    setRange(RANGE_2G, ADDR_TWO);
    
    wait(0.1);
    
    while(1)
    {
        pc.printf("Read data from AT24C512 \r\n");
        uint16_t x1 = getX(ADDR_ONE);
        uint16_t y1 = getY(ADDR_ONE);
        uint16_t z1 = getZ(ADDR_ONE);
        
        uint16_t x2 = getX(ADDR_TWO);
        uint16_t y2 = getY(ADDR_TWO);
        uint16_t z2 = getZ(ADDR_TWO);
        pc.printf("Accel one: x %d y %d z %d\r\n", x1, y1, z1);
        pc.printf("Accel two: x %d y %d z %d\r\n", x2, y2, z2);
        pc.printf("\r\n");
        wait(1);
    }
}