Intel® XDK IoT Node.js* UART Serial Communication App

See LICENSE.md for license terms and conditions.

This sample application is distributed as part of the Intel® XDK. It can also be downloaded or cloned directly from its git repo on the public IntelXDK GitHub* site.

For help getting started developing applications with the Intel XDK, please start with the Intel XDK documentation.

See also, the mraa library documentation for details regarding supported boards and the mraa library API and the upm library documentation for information regarding the upm sensor and actuator library APIs.

App Overview

A simple node.js application that demonstrates writing data via a serial port, on select Intel IoT development boards. This app uses the mraa Uart object to write to the selected serial port's TxD (Transmit Data) pin. This is a convenient way to print debug messages from your IoT app, while it is running.

Serial communication is performed via an onboard UART (Universal Asynchronous Receiver/Transmitter). UARTs are serial I/O devices commonly associated with RS-232 and COM ports.

Following are some board-specific notes to help you use this app with your specific IoT hardware device.

Intel® NUC DE3815 + Arduino 101

The "firmata" development platform (Intel NUC/Gateway plus an attached Arduino 101) is not supported by this sample.

Intel® Galileo Board for Arduino (Gen1)

The Intel Galileo Gen1 board provides access to two UART controllers:

• Uart(0) is “UART TTL” compatible and accessed via pins 0 and 1 of the 18-pin Arduino compatible header (near the top-right corner of the board, just above the Intel Galileo logo).

  To monitor data printed via Uart(0), connect to pin 1 (TxD), directly on your Galileo board, or by using the UART slot of a Seeed Base Shield or equivalent mezzanine board, if available.

• Uart("/dev/tty???") is accessed via a 3.5mm audio jack (located near the Ethernet jack).

  This UART must be initialized with mraa using its device name.

See also: https://www.arduino.cc/en/ArduinoCertified/IntelGalileo

Intel® Galileo Board for Arduino (Gen2)

The Intel Galileo Gen2 board provides access to two UART controllers:

• Uart(0) is “UART TTL” compatible and accessible via pins 0 and 1 of the 18-pin Arduino compatible header (near the top-right corner of the board, just above the Intel Galileo logo).

  To monitor data printed via Uart(0), connect to pin 1 (TxD), directly on your Galileo board, or by using the UART slot of a Seeed Base Shield or equivalent mezzanine board, if available.

• Uart("/dev/tty???") is available via the 6-pin 3.3V USB TTL FTDI header located near the Ethernet jack.

  This UART must be initialized with mraa using its device name.

See also: https://www.arduino.cc/en/ArduinoCertified/IntelGalileoGen2

Intel® Edison Board for Arduino

The Intel Edison board provides access to three UART controllers:

• Uart(0) is “UART TTL” compatible and accessible via pins 0 and 1 of the 18-pin Arduino compatible header (along the bottom of the board, near the Edison CPU module).

  To monitor data printed via Uart(0), connect to pin 1 (TxD), directly on your Edison board or by using the UART slot of a Seeed Base Shield or equivalent mezzanine board, if available.

• Uart("/dev/ttyGS0") is accessed as part of the USB “multifunction gadget” interface.

  This “Multifunction Composite Gadget” interface provides access to a serial console, RNDIS Ethernet interface and USB mass storage device. It is the uppermost of two micro-USB connectors, located along the right edge of the board (J16). This port is only active when SW1 (located directly above the micro-USB connector) is set to “device mode,” which is the switch position closest to the micro-USB connector.

  This UART must be initialized with mraa using its device name.

• Uart("/dev/ttyMFD2") is the Linux kernel debug port. It is the micro-USB connector located at the lower-right corner of the board (J3).

  This is a very useful port to connect to for debugging, especially when trying to isolate boot problems. The kernel generates its “debug spew” to this port at 115,200 baud. You may find it useful to attach a PuTTY or similar serial terminal console application to this USB port.

  This UART must be initialized with mraa using its device name.

See also: https://www.arduino.cc/en/ArduinoCertified/IntelEdison

Intel® Joule™ 570x Developer Kit

Because the Joule BIOS does not enumerate the onboard UART devices, you must use the Linux /dev/tty?? device names to access them. This means you cannot pass in an integer value "UART pin number" to identify the onboard Joule UART devices, like you can with the Edison and Galileo boards.

• Uart("/dev/ttyS0") is “UART TTL” compatible. The TxD (Transmit) pin of this UART is accessed via pin 7 of the J12 connector (the top-most 40-pin header). The other UART pins (RxD, RTS and CTS) can be located on J13 (the other 40-pin header) at pins 28, 30 and 32 (respectively). Because this app only writes to the UART, it is only necessary to monitor the TxD pin.

  This UART must be initialized with mraa using its device name.

  Referred to as "UART port 0" in the Joule module hardware documentation.

• Uart("/dev/ttyS1") is “UART TTL” compatible. The TxD (Transmit) pin of this UART is accessed via pin 22 of the J12 connector (the top-most 40-pin header). The RxD pin is located at pin 24 of J12. There are no RTS and CTS pins associated with this UART. Because this app only writes to the UART, it is only necessary to monitor the TxD pin.

  This UART must be initialized with mraa using its device name.

  Referred to as "UART port 1" in the Joule module hardware documentation.

• Uart("/dev/ttyS2") is accessed via the USB “FTDI” interface.

  This USB “FTDI” interface provides access to a serial to USB console device. It is the micro-USB connector (j9) located between the large Type A USB connector and the small micro-HDMI connector. This port is typically configured to listen for a login using the Linux getty daemon. This means that data you write to this port may be intermixed with serial data emitted by other services that are also connected to the port.

  This UART must be initialized with mraa using its device name.

  Referred to as "UART port 2" in the Joule module hardware documentation. The hardware documentation states that "UART port 2 is used as a debug port for BIOS messages during boot."

• Uart("/dev/ttyS3") is “UART TTL” compatible. The TxD (Transmit) pin of this UART is accessed via pin 34 of the J13 connector (the inner 40-pin header). The other UART pins (RxD, RTS and CTS) are also located on J13, at pins 36, 38 and 40 (respectively). Because this app only writes to the UART, it is only necessary to monitor the TxD pin.

  This UART must be initialized with mraa using its device name.

  Referred to as "ISH UART port 0" in the Joule module hardware documentation.

Intel® NUC or Gateway

Like the Joule (above) you must use the Linux /dev/tty?? device names to access the local UART devices on your IoT system (NUC or Gateway device) when using the mraa library; the use of a USB-attached Arduino 101 that is running the firmata sketch app is not supported by this sample. Any Arduino 101 attached to your NUC/Gateway device will be ignored by this sample.

Important App Files

• main.js
• package.json

Important Project Files

• README.md
• LICENSE.md
• <project-name>.xdk

Tested IoT Node.js Platforms

• Intel® Galileo Board for Arduino
• Intel® Edison Board for Arduino
• Intel® Joule™ 570x Developer Kit
• Intel® NUC DE3815
• Intel® NUC5i7RYH

See the Intel® NUC support page and the Intel Product Specifications search tool for detailed hardware specifications and support.

This sample can run on other IoT Node.js development platforms, but they must include the appropriate hardware. If you use an IoT device that is not listed above you may have to make changes to the I/O initialization and configuration code in the cfg-app-platform.js module before it will work on those other platforms. See this device software prerequisites page for help configuring the software on your IoT device so it can be used with the Intel XDK.