FTDI to single line

[IvoS]

I have FTDI friend from Adafruit https://cdn-shop.adafruit.com/1200x900/284-00.jpg and I am thinking if there is a way to connect it as a single line programmer. I have this gyro system  https://www.beastx.com/eng/microbeast_plus.php and I believe they use single line UART to USB for PC connection interface. Microbeastx sells their own USB2SYS programmer but I believe there is FTDI chip inside anyway. Would there be a way to wire my FTDI friend to single line programmer? I just tried to hook it up to PC and the Microbeastx software detect my Adafruit FTDI on COM3. So yes, it is recognized, just don't know how to wire it.

[radiolistener]

tx to rx and rx to tx 

[IvoS]

Not available. Only GND and signal wire output. 2wires total.

[Renate]

Yes, it is a one wire.
I'd check a few things first.
With the unit powered check the voltage on the pin.
See if it's the full battery voltage or some lower regulated voltage.
With the unit powered off, using regular ohm range (not diode) check the resistance from the + pin to the SYS pin.

In the sleaziest case you can just connect TX from the FTDI to the cathode of a diode, anode to the SYS pin.
Then connect the SYS pin to a 1 k resistor to the RX of the FTDI.

In a cleaner version, you can feed TX to an inverter (either IC or just another transistor) and feed that into a MOSFET (like a 2N7000).
The RX could be handled through a level shifter or just another 2N7000 and an inverter.

I did about the same for the OBD-1 on my Chevy which is a 5 V one wire sort of interface (not CAN bus).

[Ian.M]

Some FTDI USB UART chips have pin modes intended for I2C bus operation, so support configuring TX as open drain and simply strapping it to RX.   However you need to configure it so if you aren't 100% certain the official FTDI based programmer does that, Renate's suggestions will be safer.  If you use a simple diode it should be Schottky to get a low enough logic '0' level.