Hi I'm new to arduino and I am trying to interface an old UMI rt100 robotic arm with an arduino pro mini so I can control its movement with a PS2 control ;D The robot arm has two internal "intelligent peripherals" lol and I basically interface with RS232 connection which I have installed correctly using a MAXX232 (I think I don't have the dev board in front of me 
) Basically I have ran into 2 problems just wandering if anyone could help or show me where to find some 
so firstly I noticed the rx tx pins are also the ones used by usb, and without even uploading anything major my compiler has errors as my robot arm is having a fight with usb, how do I make them share appropriately? Or can I achieve just as good serial interface using a softwareserial library?
Also I need to use specific commands which are documented for the robot arm, I have implemented and defined them in a header file for ease of use, but all serial examples using the serial library so far only throw ASCII around, could anyone show me an example of sending raw user defined bytes? And maybe just explain how I parity and stop bits work with the serial libraries as I need even and 1 stop bit.
Thanks in advance for any help!
Cheers,
Hazz
You can either use the new software serial library NewSoftSerial | Arduiniana or have a switch to remove the serial connections while you upload like I used in this project NewSoftSerial | Arduiniana
To send say a byte of data
d=12; // or any other number
Serial.print(d,BYTE);
See Serial.print() - Arduino Reference
how I parity and stop bits work with the serial libraries
They are just parameters you set.
Cheers mate!
kinda sux i cant have usb connected because i havnt sourced an external power source yet, I'll have to get onto that asap, i really need to use the rx and tx because im really pushed for pins at the moment, reckon u could fix up ur link to show me ur switch?
Cheers,
Hazz
Something else to keep in mind (although, if you have the spec sheet for the robot in front of you, that will tell you) - the RS-232 interface on the robot is likely expecting true RS-232, not TTL. You may need a convertor chip (MAX232 or the like) in order to use the Arduino's built in hardware UART or a Software Serial interface library...
reckon u could fix up ur link to show me ur switch?
Look and see how I did it on this project:-
http://www.thebox.myzen.co.uk/Hardware/MIDI_Shield.html
I was switching between the USB and the MIDI input / output. The same thing applies in your case.
@cr0sh
he did say in the first post:-
I basically interface with RS232 connection which I have installed correctly using a MAXX232