Internal OLED Display not functioning | Heltec Lora 32 V2

[Sascha]

Hi everyone,

I have a brand new Heltec Lora ESP 32 V2 whose internal OLED display refuses to work after flashing.
The display itself should be okay, as it worked with the original firmware it was shipped with.

Using the serial monitor I can't see any error messages,
except (after while):

[I][esp32-hal-i2c.c:1138] i2cProcQueue(): Bus busy, reinit

The module connects to my wifi and sends its position, just no display. So I think this is the only problem.

Any idea where the problem might be here? I'm using FW 21.50.0 and i think also the newest Vusual Stuidion / Platformio version.

Sascha, DL5SMB

[Sascha]

Okay, it seems as if the wrong board gets detected.
Sorry, should have noticed this earlier

I LoRa_APRS_iGate.cpp 47 : LoRa APRS iGate by OE5BPA (Peter Buchegger)
I LoRa_APRS_iGate.cpp 48 : Version: 21.50.0
I LoRa_APRS_iGate.cpp 79 : Board TTGO_LORA32_V2 loaded.`

So is there somewhere an override option for the hardware-detection?

[Sascha]

And I am one step closer to the final solution.

After reflashing I noticed other error messages following the first boot,
when the hardware is detected and set:

Quit: Ctrl+C | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---
I LoRa_APRS_iGate.cpp 47 : LoRa APRS iGate by OE5BPA (Peter Buchegger)
I LoRa_APRS_iGate.cpp 48 : Version: 21.50.0
W lib\ConfigurationManagement\configuration.cpp 27 : Failed to read file, using default configuration.
I lib\BoardFinder\BoardFinder.cpp 13 : looking for a board config.
I lib\BoardFinder\BoardFinder.cpp 14 : searching for OLED...
[E][esp32-hal-i2c.c:1434] i2cCheckLineState(): Bus Invalid State, TwoWire() Can't init sda=0, scl=0
W lib\BoardFinder\BoardFinder.cpp 73 : issue with wire
D lib\BoardFinder\BoardFinder.cpp 123 : -1
D lib\BoardFinder\BoardFinder.cpp 128 : power chip NOT found
I lib\BoardFinder\BoardFinder.cpp 26 : found a board config: TTGO_LORA32_V2
I LoRa_APRS_iGate.cpp 74 : will restart board now!
I LoRa_APRS_iGate.cpp 47 : LoRa APRS iGate by OE5BPA (Peter Buchegger)
I LoRa_APRS_iGate.cpp 48 : Version: 21.50.0
I LoRa_APRS_iGate.cpp 79 : Board TTGO_LORA32_V2 loaded.

So after some googling I found a post where a user adviced to connect GPIO21 (Vext power) to GND.

This is worked at least partially for me.

Now instead of a TTGO_LORA32_V2 a Heltec WiFI LoRa 32v 1 gets detected.

I do have a working OLED-display now, but as some pins for LoRa changed between V1 and V2 (which i have), I am not sure if LoRa is working yet and correctly.

If I am interpreting BoardFinder.cpp correctly, there are no differenced in the connecting pins, as LoRa Dio1 and Dio2 are not in use / defined, is this correct? But if so, why distinguishing these board revisions at all?

And where might this detection problem be? Is this somehow connected to pull-ups?

I am afraid my coding skills are not good enough to understand how the detection works in the source code.

Also I think it might really make sense to get an option to override detection with a configuration flag in the is-cfg.json.

[Peter Buchegger]

Thanks for your detailed explanation.

1. can you post a link with our exact board? I was always thinking it is the same as the one from Lilygo. I will buy one to have one for testing ;)

2. to fix your current issue you can force the board in the config file is-cfg.json:
   add the board setting to the config:

	},
	"ntp_server": "pool.ntp.org",
        "board": "HELTEC_WIFI_LORA_32_V2"
}

be sure everything is in correct json format (don't forget the , !).

If this is not working, activate the ftp server, download the config via an ftp client (simple ftp, no sftp oder ftps!), change the board name and upload it again to the board.

[Sascha]

Hi Peterus,

thanks for your answer.

[This](https://www.aliexpress.com/item/33018609928.html?spm=a2g0o.order_detail.0.0.18036368PfLIOj is the board I bought.

I'll check what happens if I select the board according to your instructions in the config-file.