I2C interface for MAG3110 wirtten for electric imp

MAG3110_electric_imp

// Define the Sensor Address
const ADDR = 0x1C;
 
// Define register map
const DR_STATUS = "\x00";
const OUT_X_MSB = "\x01";
const OUT_X_LSB = "\x02";
const OUT_Y_MSB = "\x03";
const OUT_Y_LSB = "\x04";
const OUT_Z_MSB = "\x05";
const OUT_Z_LSB = "\x06";
const WHO_AM_I = "\x07";
const SYSMOD = "\x08";
const OFF_X_MSB = "\x09";
const OFF_X_LSB = "\x0A";
const OFF_Y_MSB = "\x0B";
const OFF_Y_LSB = "\x0C";
const OFF_Z_MSB = "\x0D";
const OFF_Z_LSB = "\x0E";
const DIE_TEMP = "\x0F";
const CTRL_REG1 = "\x10";
const CTRL_REG2 = "\x11";


const DR_1280 = "\x00";
const DR_640 = "\x20";
const DR_320 = "\x40";
const DR_160 = "\x50";
const DR_80  = "\x80";
const DR_40  = "\xA0";
const DR_20  = "\xC0";
const DR_10  = "\xE0";

const OSR_16 = "\x00";
const OSR_32 = "\x08";
const OSR_64 = "\x10";
const OSR_128 = "\x18";
const FAST_READ = "\x04";
const TRIGGER_MEAS = "\x02";
const ACTIVE = "\x01";

const AUTO_MRST_EN = "\x80";
const RAW = "\x20";
const MAG_RST = "\x10";
 
 
// Specify the update rate in seconds
const update_rate = 5;
 
// Define the i2c periphrial being used
i2c <- hardware.i2c89;
int <- hardware.pin7;

x_min <- 32767
x_min_cyc <- 32767
y_min <- 32767
z_min <- 32767

x_max <- -32767
x_max_cyc <- -32767
y_max <- -32767
z_max <- -32767

x_prev <- 0

x_count <- 0
x_int <- 0
x_int_neg <- 0
x_hist <- false
x_dd <- false
x_hf <- false
z_dd <- false

debounce <- 130

x_start <- 0
x_trigs <- 0
x_trigs_hf <- 0
y_trigs <- 0
z_trigs <- 0

x_thresh <- 0
y_thresh <- 0
z_thresh <- 0

x_spread <- 0
y_spread <- 0
z_spread <- 0

calibrate <- 0;

buffer_size <- 800;
index <- 0;
buffer <- array(buffer_size);

// Configure said periphrial
i2c.configure(CLOCK_SPEED_400_KHZ);
i2c.write(ADDR,CTRL_REG2+AUTO_MRST_EN)
i2c.write(ADDR,CTRL_REG1+"\x01")
local data = i2c.read(ADDR,OUT_X_MSB,6);

function mag_isr() {
  if (int.read()==1)
  {
    local data = i2c.read(ADDR,OUT_X_MSB,6);  
    if (calibrate ==0) {
      server.log("calibrate")
      calibrate <- 1;
      i2c.write(ADDR,OFF_X_MSB+data)
    }
    else
    {
      local x = data[0]<<8 | data[1]
      if (x & 0x8000) {x = -((~x & 0x7FFF) + 1);}
      local y = data[2]<<8 | data[3]
      if (y & 0x8000) {y = -((~y & 0x7FFF) + 1);}
      local z = data[4]<<8 | data[5]
      if (z & 0x8000) {z = -((~z & 0x7FFF) + 1);}
      
      if (x<x_min) {x_min = x; x_spread = x_max-x_min; x_thresh = x_min+x_spread/2}
      if (x<x_min_cyc) {x_min_cyc = x}
      if (y<y_min) {y_min = y; y_spread = y_max-y_min; y_thresh = y_min+y_spread/2}
      if (z<z_min) {z_min = z; z_spread = z_max-z_min; z_thresh = z_min+z_spread/2}
      
      if (x>x_max) {x_max = x; x_spread = x_max-x_min; x_thresh = x_min+x_spread/2}
      if (x>x_max_cyc) {x_max_cyc = x}
      if (y>y_max) {y_max = y; y_spread = y_max-y_min; y_thresh = y_min+y_spread/2}
      if (z>z_max) {z_max = z; z_spread = z_max-z_min; z_thresh = z_min+z_spread/2}
      
      if (x>x_thresh) {
        if (!x_hf){
          x_hf = true
          x_trigs_hf++
        }
        x_count++
        x_int += (x-x_thresh)
        if (x_int>debounce) {
          if (!x_dd) {
              x_trigs++
              x_dd=true
              x_int_neg = 0
            }
          }
        }
      else {
        x_hf = false
        x_int_neg += (x_thresh-x)
        if (x_int_neg>debounce) {
            x_int = 0
            x_dd = false
        }
      }
     
      if (index<buffer_size)
      {
        buffer[index] = [x,y,z]
        index++
      }
      else
      {
        index = 0
        agent.send("buffer",[buffer,[x_min,x_max,x_thresh,x_trigs_hf,x_trigs],[y_min,y_max,y_thresh,x_max_cyc-x_min_cyc,y_trigs],[z_min,z_max,z_thresh,z_spread,z_trigs]])
        x_trigs = 0
        x_trigs_hf = 0
        x_max_cyc = -32767
        x_min_cyc = 32767
        
      }
    }
  }
}

int.configure(DIGITAL_IN, mag_isr)