Serial output from any pin?

Hardware Arduino Zero
1

I need to output serial packets from a standard I/O pin without remapping a SERCOM port to it as i only need output (TX) not input (RX) and SERCOM requires a valid pin for each, more specifically a valid pair. i know this is possible as it can be done with bit-banging the data but that seems like an extremely crude solution, despite my googling i have been unable to find any libraries for- or discussions about- this topic.

the arduino is a ZERO so 48mhz clock and can directly handle 32bit operations. does anyone know of a library for this purpose or a "standard" / "propper" way of doing this?.

it shouldn't be relevant but the application is SBUS output which is a 100000 baud 8E2 inverted serial signal, the inversion is done with external hardware. the SBUS packet is stored as an array of bit-shifted 8-bit bytes.

2

I'm not familiar with the processor on your board and I don't have the board.

Maybe below from the M0 datasheet might point you in the right direction:

3

Well, there is Duino-hacks/DumbTXSWS/src/DumbTXSWS.cpp at master · WestfW/Duino-hacks · GitHub (bit-banging), but it depends on delayMicroseconds() and digitalWrite() being "fast" compared to the bit time, and I suspect that it won't do very well on a 48MHz SAMD at 100kbps.

Can you pick a pin that is tied to TxD for one of the other Sercom peripherals? A custom SerCom driver could avoid configuring the receive pin...

SERCOM requires a valid pin for each, more specifically a valid pair.

Are you that short of pins? Just because you define and enable an RX pin, doesn't mean you have to actually connect anything to it (although a pullup is a good idea!)