Trying to read MSP from Flight Controller via Serial1 (pins 0,1) but can't

[king_of_cups]

Total newbie here. I'm using a Teensy 4.1 to power a nerf blaster. It needs to read MSP from an FPV flight controller, which I've assigned to Serial1 (which as far as I can tell, is pins 0 and 1). I can't get the Teensy to communicate with the UARTs on the FC, and I'm wondering whether there's some trick to it that I otherwise wouldn't know about. I've attached my .ino file. Thanks for any help you can provide!

 

[MarkT]

Is the flight controller 3.3V ? It needs to be to talk to the T4, otherwise it'll roast it.

 

[king_of_cups]

Is the flight controller 3.3V ? It needs to be to talk to the T4, otherwise it'll roast it.

Yes, it’s 3.3V.

 

[MarkT]

You are wiring TX <-> RX in both directions?

 

[king_of_cups]

You are wiring TX <-> RX in both directions?

Yes, FC TX > Teensy RX, and vice versa. I’m swapping FCs to see if it’s a problem with that or with the board.

 

[MarkT]

Can you snoop the traffic?

 

[king_of_cups]

Can you snoop the traffic?

Sorry, I don’t know what that means

 

[MarkT]

Can you adding debugging output then?

 

[mjs513]

Silly question. I see you have

FC_SERIAL.begin(115200);

is that the same serial speed that the Betaflight FC is transmitting the data at?