Nerves serial TTY help

I’m attempting to get a Sparkfun FTDI cable to connect the serial console to my Macbook with no luck so far. Looking at the cable schematic I have hooked the TXD/orange andRXD/yellow to the corresponding TXD & RXD pins on the Rpi and have setup the erlinit.config per the Nerves FAQ nerves/ at main · nerves-project/nerves · GitHub w ttyS0 set for my Rpi3. Guessing the firmware boots fine (it did before) but can’t connect via screen get some “device is busy” followed by “could not find a PTY” … any ideas, mistakes, or troubleshooting I should do next?

@craigbeck You may get a better response in the Nerves channel on the Elixir slack. Its a pretty active and very helpful community for this kind of topic.

We’re trying to do a better job of answering questions here instead of in Slack because they’re a lot easier for others to find later if they’re here.

One thing to clarify initially that often trips people up when they’re new to using UARTs: are you connecting the cable’s TX to the board’s TX? The correct way is to connect TX on the cable to RX on the board, and likewise with the cable’s RX to the board’s TX.

TX means “transmit” and RX means “receive”, so you want one to be transmitting on the pin that the other is receiving on.


Ha, well that sounds like it. I’ve connected RX -> RX and TX -> TX. I’ll confirm when I get home to it.

Thanks, @kip. I also asked there, but this seemed like a better place to archive any solution.

Thanks @GregMefford that was it!

Would never have through to flip those… used to matching everything up

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Perfect! Glad you got it working! :rocket:

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