Node.js for Embedded Systems

Chapter 4. The Tessel 2

OK, so you can blink from the command line and via Firmata or Espruino, but how about running full Node.js on a board? This is what a Tessel allows you to do.

Besides full Node.js compatibility, the Tessel board is great to get started working with the embedded Internet. The Tessel 2 hardware combines a microcontroller with a system-on-a-chip (SoC) that includes all-important building blocks for routing data in a network.

Hardware

The Tessel 2 is shown in Figure 4-1. The Tessel 2 combines a microcontroller with a more powerful microprocessor.

Figure 4-1. The Tessel T2 board from Rick Waldron’s “Examples with fritzing diagrams”

The idea of combining microcontrollers with a microprocessor is similar to the distributed nervous system of your body. The brain (processor) does the complex thinking, while other nervous centers in the body (controllers) coordinate the actions of hands, arms, and legs at the speed you need to react.

The “brain” in the Tessel 2 is the main processor with an operating system. Tessel 2 uses a 580 MHz Mediatek MT7620n SoC, a chip commonly found in WiFi routers. The Tessel main processor is powerful enough to run Node.js. It has 64 MB DDR2 RAM and 32 MB flash to store applications. For connectivity, there is 802.11bgn WiFi and an Ethernet port for an ultra-reliable wired connection.

For electronic peripherals, the nervous backbone ...