Serial Communication problem

Hi guys,

Just started working with Arduino, worked on Microchips before.

I use Arduino Mega2560. My problem with serial port is that it works perfectly with the usb connection to the computer, but whenever I other serial - I get jibbrish on both writing and reading. Even if I use the usb serial only wire my rs232 cable to the TX0,RX0 pins the problem remains the same.

tried also the NewSoftSerial library and got the same problem.

can anyone please help me it’s driving me crazy.

thanks,

jonathan.

jibbrish normally means one of several things.

  1. Wrong baud rate on TX or RX side of the link

  2. No common ground

  3. Noise on long cable runs

  4. Incorrect voltage levels.

If the serial protocol via USB works, then I would want to see how you wired from the Arduino to the DB-9 connector you connected to an RS-232 serial port. I will bet that you may have forgotten to add a level converter. If you did, then I will bet its a baud rate mismatch.

Its was the level converter I wasn’t aware of. and thanks.

Anyone search this topic in the future go here:

http://www.arduino.cc/cgi-bin/yabb2/YaB … 028176/6#6

You don’t even need to leave Sparkfun. Here is a tutorial on the issue:

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