Maxim Integrated / Mbed 2 deprecated DeepCover Embedded Security in IoT

MAXREFDES143#: DeepCover Embedded Security in IoT Authenticated Sensing & Notification

Dependencies:   MaximInterface mbed

The MAXREFDES143# is an Internet of Things (IoT) embedded security reference design, built to protect an industrial sensing node by means of authentication and notification to a web server. The hardware includes a peripheral module representing a protected sensor node monitoring operating temperature and remaining life of a filter (simulated through ambient light sensing) and an mbed shield representing a controller node responsible for monitoring one or more sensor nodes. The design is hierarchical with each controller node communicating data from connected sensor nodes to a web server that maintains a centralized log and dispatches notifications as necessary. The mbed shield contains a Wi-Fi module, a DS2465 coprocessor with 1-Wire® master function, an LCD, LEDs, and pushbuttons. The protected sensor node contains a DS28E15 authenticator, a DS7505 temperature sensor, and a MAX44009 light sensor. The mbed shield communicates to a web server by the onboard Wi-Fi module and to the protected sensor node with I2C and 1-Wire. The MAXREFDES143# is equipped with a standard shield connector for immediate testing using an mbed board such as the MAX32600MBED#. The simplicity of this design enables rapid integration into any star-topology IoT network requiring the heightened security with low overhead provided by the SHA-256 symmetric-key algorithm.

More information about the MAXREFDES143# is available on the Maxim Integrated website.

MAX44009.cpp

Committer:
IanBenzMaxim
Date:
2016-05-12
Revision:
6:b6bafd0a7013
Parent:
1:e1c7c1c636af
Child:
15:8cc4cdea59da

File content as of revision 6:b6bafd0a7013:

/*******************************************************************************
* Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
*
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* Software is furnished to do so, subject to the following conditions:
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* The above copyright notice and this permission notice shall be included
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
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* Except as contained in this notice, the name of Maxim Integrated
* Products, Inc. shall not be used except as stated in the Maxim Integrated
* Products, Inc. Branding Policy.
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* The mere transfer of this software does not imply any licenses
* of trade secrets, proprietary technology, copyrights, patents,
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*******************************************************************************
*/

#include "MAX44009.hpp"
#include "I2C.h"

static const int I2C_OK = 0;

MAX44009::MAX44009(mbed::I2C & I2C_interface, uint8_t I2C_address)
  : m_I2C_interface(I2C_interface), m_I2C_address(I2C_address)
{
  
}

MAX44009::Result MAX44009::read_current_lux(double & lux) const
{
  char I2C_data;
  uint8_t mantissa, exponent;
  
  I2C_data = Lux_High_Byte_Reg;
  if (m_I2C_interface.write(m_I2C_address, &I2C_data, 1, true) != I2C_OK)
  {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  if (m_I2C_interface.read(m_I2C_address, &I2C_data, 1, true) != I2C_OK)
  {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  mantissa = (I2C_data << 4);
  exponent = (I2C_data >> 4);
  
  I2C_data = Lux_Low_Byte_Reg;
  if (m_I2C_interface.write(m_I2C_address, &I2C_data, 1, true) != I2C_OK)
  {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  if (m_I2C_interface.read(m_I2C_address, &I2C_data, 1, false) != I2C_OK)
  {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  mantissa |= (I2C_data & 0x0F);
  
  unsigned long calc_result = 1;
  if (exponent > 0)
  {
    calc_result <<= exponent;
  }
  calc_result *= mantissa;
  lux = calc_result * 0.045;
  
  return Success;
}