More features, less power.

The Thread Connectivity Platform that NXP announced at last week’s ARM TechCon was a physical embodiment of many of the show’s themes of security, the Internet of Things (IoT), low power, ease of programming and use, and widespread connectivity.

The Thread Platform is based on the JN5179 wirelessly enabled microcontroller, with an ARM Cortex-M3 CPU at its core and a 2.45-GHz IEEE 802.15.4 radio providing the wireless connection. Along with other features, its calling card is its experimental use of the ARM mbed OS for the IoT, which helps simplify writing software to control hardware devices connecting to the cloud. It also makes it easy to create embedded connected solutions such as lighting and gateway devices for the IoT market. The mbed OS is currently under review by ARM.

The heart of the IoT Thread Platform from NXP is its JN5179 motherboard

In the meantime, the Platform has a number of nifty features that make it suitable for ultra low-power applications such as home automation, smart energy, Light Link (lighting control based on ZigBee) and remote-control applications.

For starters, it includes a DC/DC converter. Given the precious nature of board real estate, I asked Ian Morris, Principal Wireless Firmware Applications Engineer at NXP Semiconductors, why it was included. He explained that with the on-board DC/DC, you could run the MCU off the light’s LED string directly by connecting to the DC/DC converter, which will in turn down-convert to power the MCU. This eliminates the need for an AC/DC converter, thereby reducing the number of ICs from three to two (LED driver and MCU). Pretty nifty.

For security, the Platform has a memory protection unit (MPU) that lets you run software in protected sandboxes without access to other areas of memory or peripherals. In that way, if a rogue piece of software does get in there, it can’t do any damage. Also, Thread encrypts all data running over the network using a 128-bit AES key.

“But that key needs to be stored securely, because what people don’t realize is that when you discard that secure device, it contains the key to your network,” said Morris, which of course leaves your network susceptible to hacking.

This is where NXP’s Secure Element technology comes in. It’s the same technology used in government- issued e-passports and once it’s embedded in the device, such as a light bulb, it securely store the key, even when you dump it.

However, getting that key to the device is often a security risk, so what NXP adds to its kit is NFC: a user simply brings the new device close to-- or taps--the home gateway, and the key is transmitted and the device is commissioned accordingly. Using NFC to commission the device, versus, say, Wi-Fi or Bluetooth, greatly reduces the possibility of sniffing.

While the JN5179 microcontroller samples are available now, full evaluation kits for the JN5179 mbed modules won’t be available until early next year. 

Other features of the Thread Platform include:

  • 512 kbytes/32 kbytes/4 kbytes (Flash/RAM/EEPROM)
  • OTA (over the air) download capability
  • 1 MHz to 32 MHz clock speed for low power
  • Dual PAN ID support
  • Fail-safe I2C-bus interface. operates as either master or slave
  • 2 low-power sleep counters
  • SPI-bus master and slave port, 2 simultaneous selects
  • Variable instruction width for high coding efficiency
  • Multi-stage instruction pipeline
  • Data EEPROM with guaranteed 100 k write operations
  • Supply voltage monitor with 8 programmable thresholds
  • Battery and temperature sensors
  • 6-input 10-bit ADC
  • Analog comparator
  • Digital monitor for ADC
  • Battery and temperature sensors
  • Watchdog timer and POR
  • Standby power controller
  • Up to 18 Digital IO (DIO) and 2 digital outputs pins

Get the full JN5179 wireless MCU description here on the ARM mbed site