I can see that 3DR sells 3.3v FTDI cables. But I was not able to confirm by searching this forum if 3.3v is the only option or if a cable with TTL level of 5v will also work ?
I already have a 5V cable and I just don't want to try it and fry my module.
Ok. I spent some time searching this forum but I did not really read the product page on the 3DR store. And it says:
"Interface to the module is via standard 5V-tolerant TTL serial / FTDI USB serial."
So why is a 3.3v cable sold with the module.
Either cable will work. The 3DR radio actually works for input power down to about 3v, and the serial interface is 5V tolerant.
Note that VCC is 5V, only the signal wires are 3.3V according to 3DR and the cable manufacturer's spec sheet.
3DR's page states: "Note: The TX/RX signals are 3.3volts, making it even more flexible, the power supply is 5volts (red wire)."
Why do they state it is more flexible? Will a 3.3V signal work with a 5V system?
Also, if your board is using 5v signaling, I hope that won't harm the RS232/USB convertor chip inside the cable (which expects 3.3V). took me awhile to realize FTDI is simply a company which makes the RS232/USB convertor chip...dumb idea whoever decided to refer to them as FTDI instead of RS232.
Just a quick question did the 5v signal cause any harm to the OSD ? I've just bought a FTDI breakout but see now that it's 5v logic .