Arduino Serial to Ethernet Utilizing an NSLU2 – Technical Details

Here is another selection for getting your Arduino (or other PIC) connected to your network (ethernet) – use a classic NSLU2!

The NSLU2 and Arduino both talk TTL, however the NSLU2 is 3.3v and Arduino is 5v. Simple fix – put in a resistor!

Only 3 wires are required – pins 2, 3 and 4 on the NSLU2. You may not want to connect the power pin. Per the table below, try to find the white stripe – that’s the power pin.

NSLU2 – pin-out of the J2 serial port

Pin 1 – 3.3v, pin 1 includes a white stripe alongside it

Pin 2 – RXD, receive from Arduino to NSLU2 (must have resistor)

Pin 3 – TXD, transmit from NSLU2 to Arduino

Pin 4 – GND, ground connection

This short article is written in reference to the “Freeduino” – a BBB (bare bones board) type. Make sure everything is powered off and unplugged. Then, connect the TTL pins labeled “RX”, “TX” and “GND” on the BBB to the proper pins on the NSLU2. The 4 serial port TTL pins on the NSLU2 are visible just underneath the battery to the right.

You have to place a 10k resistor between the Arduino and the NSLU2 on pin 2 of the NSLU2 therefore the 5v from the Arduino are reduced to safe levels.

Now power up the Arduino and NSLU2 that’s flased with Debian (SlugOS should work also). Install minicom (apt-get) and start up minicom and set the serial port to ttyS0, 9600, 8N1.

If the connections are correct, the TTL pins/port on the Arduino and NSLU2 are functional you must now see the output from the Arduino. If you may not see anything, be sure you have pre-programmed your Arduino with an application that outputs text at the proper baud rate. Also try powering off both units, power back up and try again. When you yourself have made other hardware mods such as overclocking on the NSLU2, it’s possible the serial port will not work.
You have to place a 10k resistor between the Arduino and the NSLU2 on pin 2 of the NSLU2 therefore the 5v from the Arduino are reduced to safe levels.

Now power up the Arduino and NSLU2 that’s flased with Debian (SlugOS should work also). Install minicom (apt-get) and start up minicom and set the serial port to ttyS0, 9600, 8N1.

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