Removing Resistors Jumpers R62 & R63

Hi, where is the resistor jumpers R62 & R63 and how do I remove it?

Why would you want to do that?

You can accomplish the same thing by logging into the Linux processor, and asserting GPIO output 23. This will put U16A into a tri-state mode, which will isolate the Linux and AVR serial ports. You can then use the AVR serial port using header pins 0 and 1, and the Linux port using test points TP34 & TP35 (if you can find them.)

To disable the serial port bridge:

echo 0 > /sys/class/gpio/gpio23/value

To re-enable the serial port bridge:

echo 1 > /sys/class/gpio/gpio23/value

The advantage here is that you are making no physical modifications to your Yun. The downside is that you must run the first command above every time the Yun boots (easiest way it to put it in /etc/rc.local) and the serial port will still be connected between the two processors until you actually do run that command.

If you really do want to remove those resistors, how would you do it? With a soldering iron. That will, of course, invalidate any warranty, and could cause permanent damage to your Yun if you are not careful.

Thanks for the very informative reply. I was told that I need to remove the resistors in order for the board to work with a skywire development board. Have you tried using a skywire board with the YUN before? Any idea how to go about doing it?

I know nothing about skywire.

This seems like an odd thing to do, as it isolates the communications path between the AVR processor running the sketch, and the Linux system. It's this connection that makes the Yun powerful, and is the reason why the board was made. If it's necessary to break this connection, then I wonder why you want to use a Yun in the first place? It sounds like an expensive proposition.

If the skywire board is talking to the AVR processor, and is not using the Linux portion of the Yun, then you would be probably be better off using an Uno. At least it would be much cheaper.

If the skywire board is talking to the Linux side, and not using the AVR processor, then you would probably be better off using something like a Raspberry PI - the Linux side has more features and is also cheaper.

Hi ShapeShifter,

I didn't manage to follow up with this issue recently as I'm caught up with other stuff.
I manage to contact the skywire support recently. Their proposed solution is to put the board side-by-side and connect the necessary cables or cut the TX/RX pins on the development board to connect the pins separately. I guess the conclusion is I can't connect the board directly to Yun.

I've explored using PI too, but it's not suitable for my current application. I'm contemplating switching to Leonardo if it's easier to use it with the development board. Do you have knowledge on the porting of code from Yun to Leonardo?