Serial Communication (Java)

[RyanCahoon]

Why not communicate over ethernet? RoboRealm's network tables module is designed for this

http://www.roborealm.com/help/Network_Tables.php

[RyanCahoon]

To answer the original question, the AdaFruit cable you linked is meant for TTL level signals, whereas the RS-232 port uses much higher voltages. The RoboRIO does have a TTL UART port, but it's in the MXP port (pins 10 and 14, see the user manual).

[FlamingSpork]

Originally Posted by RyanCahoon

To answer the original question, the AdaFruit cable you linked is meant for TTL level signals, whereas the RS-232 port uses much higher voltages.

You could use a RS-232 to TTL adapter board based on the MAX3232 chip (most are), like this one: https://www.amazon.com/Mini-RS232-Co...ywords=max3232

We chose this one because it has solderable pads, so we didn't have to connect to the pins of a serial connector. It's reasonably easy to code with in C++. I don't know about coding it in Java, but it should be similar.

[NetArcX]

When we purchased this cable I made sure that it would be comparable with the 3.3 CMOS logic of the roborio.

On adafruits website they have a quick note on it saying "Note that we call this a "TTL cable" (since that's what they're called) but technically it's CMOS logic."

[FlamingSpork]

The Rio runs RS-232 at ±12 Volts (approx), while TTL is ±3.3 or 5. A 3.3V signal isn't enough to trigger a RS-232 circuit.

https://www.sparkfun.com/tutorials/215

[Hugh Meyer]

You might try inverting the signal. I have found when converting from TTL to RS-232 this is needed. It just depends on your hardware.

-Hugh

[adciv]

You could use a USB to Ethernet adapter on the RoboRIO and connect over Ethernet that way.

[RyanCahoon]

Originally Posted by adciv

You could use a USB to Ethernet adapter on the RoboRIO and connect over Ethernet that way.

Or just use the second ethernet port on the radio

[adciv]

Originally Posted by RyanCahoon

Or just use the second ethernet port on the radio

OP wants to avoid using that.

[RyanCahoon]

Originally Posted by adciv

OP wants to avoid using that.

Ah, I missed that