Read/Write serial data, handling reset on write.

I know that some arduino devices reset when we write to them from serial over usb.

I am planning on linking up my nano v3 into remote controlled car, and read and write data to it from beaglebone black as a brain to control servo's and read from the accelerometer, gps, xbee etc.

I'm concerned that the ~500ms that the board is rebooting when we write is going to be a problem at high speeds.

Since I want to simply use the nano as a go-between for the beaglebone and senors, servos and other stuff is there way to put it into a "pass-though" mode? How have others handled this. I appreciate any advice or experience.

Use the ICSP pins to program the NANO (this removes the bootloader though).
Remove capacitor C4 (reset) (Must then use a manual reset procedure to upload sketches).

That's the thing, do I need to upload sketches if I am controlling it from this method? I was under the impression that this was not necessary when using it in this manner. Is that not correct?

The Arduino reboots when the serial/usb port is opened, not when you write to the device. So if you open the port, once, and leave it open you should be able to communicate without reboots. There is, usually, no need to continually open and close the port. If that is not practical place a 10uF capacitor between the reset pin and a ground pin. That will prevent the board from rebooting when the port is opened and when you need to upload a program remove the cap.

You can put a 100 ohm resistor between the arduino reset pin and the +5v pin to defeat the auto reset.

Ok this is making more sense, I see that opening it is not the same as write :smiley: How does one address the pins without a sketch on the board if the is some kind of computer connected to it? ( PC / Rasberry Pi / Beaglebone )

How does one address the pins without a sketch on the board

One doesn't - one downloads a sketch which addresses the pins.