acc.lua

REG = require("i2creg")

local ACCEL_WHOAMI = 0x0D
local ACCEL_CTRL_REG1 = 0x2A
local ACCEL_M_CTRL_REG1 = 0x5B
local ACCEL_M_CTRL_REG2 = 0x5C
local ACCEL_WHOAMI_VAL = 0xC7
local ACCEL_XYZ_DATA_CFG = 0x0E
local ACCEL_OUT_X_MSB = 0x33

local ACC = {}

function ACC:new()
   local obj = {port=storm.i2c.INT, addr = 0x3c, 
                reg=REG:new(storm.i2c.INT, 0x3c)}
   setmetatable(obj, self)
   self.__index = self
   return obj
end


function ACC:init()
   local tmp = self.reg:r(ACCEL_WHOAMI)
   assert (tmp == ACCEL_WHOAMI_VAL, "accelerometer insane")
   --lets put it into standby
   self.reg:w(ACCEL_CTRL_REG1, 0x00);
   --Config magnetometer
   self.reg:w(ACCEL_M_CTRL_REG1, 0x1f)
   self.reg:w(ACCEL_M_CTRL_REG2, 0x20)
   --config accelerometer
   self.reg:w(ACCEL_XYZ_DATA_CFG, 0x01)
   --go out of standby
   self.reg:w(ACCEL_CTRL_REG1, 0x0D)
end


function ACC:get()
   -- lets be efficient and read all 6 values
   local addr = storm.array.create(1, storm.array.UINT8)
   addr:set(1, ACCEL_OUT_X_MSB)
   local rv = cord.await(storm.i2c.write,  self.port + self.addr,  storm.i2c.START, addr)
   if (rv ~= storm.i2c.OK) then
      print ("ERROR ON I2C: ",rv)
   end
   local dat = storm.array.create(12, storm.array.UINT8)
   rv = cord.await(storm.i2c.read,  self.port + self.addr,  storm.i2c.RSTART + storm.i2c.STOP, dat)
   if (rv ~= storm.i2c.OK) then
      print ("ERROR ON I2C: ",rv)
   end
   local ax = dat:get_as(storm.array.INT16_BE, 0)
   local ay = dat:get_as(storm.array.INT16_BE, 2)
   local az = dat:get_as(storm.array.INT16_BE, 4)
   local mx = dat:get_as(storm.array.INT16_BE, 6)
   local my = dat:get_as(storm.array.INT16_BE, 8)
   local mz = dat:get_as(storm.array.INT16_BE, 10)
   return ax, ay, az, mx, my, mz
end

return ACC