Hello all!
I have just bought a couple of JStamp+ dev kits from Systronix and some SC30A bluetooth modules from BlueRadios
As a novice to electronics the question I have might be simple, but I’d like to ask before I connect the two devices.
I would like to connect a BlueStamp SC30A module (http://www.blueradios.com/BR-SC30A_Rev2.0.pdf) to a JStamp+ (http://jstamp.systronix.com/jstamp_pinout.htm).
My question is, when connecting the Tx and Rx pins from the SC30A (pin 10, 11) to the Tx and Rx pins on the JStamp+ (IOD4, IOD5), do I have to put anything in between them (and what should that be then)? I guess I have to do something otherwise it’s too good to be true.
Do I have to do some voltage conversion, and later put a Max232A in between to let my PC BT understand what I’m sending? :?
JStamp+ I/O pins are said to be at TTL levels (5V), and the SC30A are at 3.3V and NOT 5V tolerant (that has been tested with bad results, I think it was Sparky who has tried this 
The reason I’m writing to you is that I don’t really understand the description of the pin voltage (please excuse my ignorance). At http://jstamp.systronix.com/jstamp_pinout.htm they are said to be 3.3 V at maximum load (which is?). On the JStamp Dev kit Quick Reference it says they will drive 5V TTL directly.
I have made some measurements with various loads on the IOD0,1,4,5 pins, e.g.
1 kOhm
unloaded / loaded (V)
Tx 4.92 / 0.04
Rx 5.02 / 4.17
100 Ohm
unloaded / loaded (V)
Tx 4.93 0.00
Rx 5.02 1.22
Please bare with me on this one - I promise to speed up my electronics skills using my new toys.
Let me know how I can manage this so I can have a first good experience using embedded Java and hardware.
Thanks,
Henke