LILYGO TTGO 1.3.40 915MHz Lora32 hardware serial (not USB)

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1

Hi all,

I have the python CLI and flasher utils working fine; I see that I am able to connect to the board via USB serial.

However, what I am trying to do is to connect via GPIO serial - ie. the pins labelled RX and TX (or any two of the other digital pins - I’ve tried configuring several pairs).

I have serial setup on COM3 (USB), with another USB-serial converter running on COM5, under Windows 10.

I currently have serial TX pin set to 28 and RX pin set to 7 (these are as per the docs here - I don’t know if this was just an example or if this is what we’re supposed to use).

This is the result of running meshtastic --post COM3 --info

Module preferences: { "mqtt": {}, "serial": { "enabled": true, "echo": true, "rxd": 7, "txd": 28, "baud": "BAUD_9600" }, "externalNotification": {}, "rangeTest": {}, "telemetry": {}, "cannedMessage": {} }

I am connecting with putty for windows, which usually works well with hardware serial devices, but I cannot get anything working. I have already tried dropping the baud rate to 9600, and I have tried with XON/XOFF and with flow control disabled.

Does anybody have any suggestions, or can perhaps let me know if this type of serial connection is not possible?

cheers
David

2

Those example pins are going to be different on different hardware, which device are you using?

3

It’s a LILYGO TTGO, ANZ region (915MHz) - it appears to be this module here:
https://meshtastic.org/docs/hardware/supported/tbeam

here’s the closeup; some of the writing on the stickers covering the chips is different, but otherwise all the features appear the same:
https://meshtastic.org/assets/files/t-beam_v1.1_pinmap-7c3402af077cdf2a5f90645561e049dc.webp

4

Try Rx 35 tx 15 for a tbeam

1 Like
5

Thanks Garth - tbeam, I’ll remember that!

I notice pins 35 and 15 are broken out/labelled on the PCB, separate from the pins labelled “rx” and “tx”.

So I now have:

Module preferences: { "mqtt": {}, "serial": { "enabled": true, "echo": true, "rxd": 35, "txd": 15, "baud": "BAUD_9600" }, "externalNotification": {}, "rangeTest": {}, "telemetry": {}, "cannedMessage": {} }

and I have connected to pins 35 & 15, still trying. I have tried a FTDI-style USB-serial adapter using the Silicon Labs CP210x driver, and I have tried an arduino with software serial.

Is there anything special I should be sending it? I just try sending keystrokes and looking for echo (I have echo turned on) but I don’t see any data yet.

6

I got to the same place, filed a bug [Bug]: 1.3 Serial Module Does not work · Issue #1707 · meshtastic/Meshtastic-device · GitHub

1 Like
7

Thanks Garth! Following with interest.