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:
19 months ago
Revision:
35:3d414ba9ab6c
Parent:
32:0a09505a656d

File content as of revision 35:3d414ba9ab6c:

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

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 {
  uint8_t I2C_data, mantissa, exponent;

  I2C_data = Lux_High_Byte_Reg;
  if (m_I2C_interface.write(m_I2C_address, reinterpret_cast<char *>(&I2C_data),
                            1, true) != I2C_OK) {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  if (m_I2C_interface.read(m_I2C_address, reinterpret_cast<char *>(&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, reinterpret_cast<char *>(&I2C_data),
                            1, true) != I2C_OK) {
    m_I2C_interface.stop();
    return Hardware_Failure;
  }
  if (m_I2C_interface.read(m_I2C_address, reinterpret_cast<char *>(&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;
}