# Big ESP32 + SX127x topic part 3

**URL:** <https://www.thethingsnetwork.org/forum/t/big-esp32-sx127x-topic-part-3/18436>\
**Category:** End Devices (Nodes)\
**Created:** [October 4, 2018, 12:58pm UTC](https://www.thethingsnetwork.org/forum/t/big-esp32-sx127x-topic-part-3/18436 "2018-10-04T12:58:13Z")\
**Posts on this page:** 1\
**Showing post:** 377

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**Author:** ![bluejedi](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/bluejedi/32/44639_2.png) [@bluejedi](https://www.thethingsnetwork.org/forum/u/bluejedi)\
**Post date:** [November 16, 2020, 4:54pm UTC](https://www.thethingsnetwork.org/forum/t/big-esp32-sx127x-topic-part-3/18436/377 "2020-11-16T16:54:41Z")

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You should read the [Topic Start](https://www.thethingsnetwork.org/forum/t/big-esp32-sx127x-topic-part-3/18436) **carefully**.

> [@TTN\_44320](#):
>
> - I use a Heltec module : OLED WIFI Lora 32.

OLED WIFI LoRa 32 is not the correct full name of your board.

Your board is one of the following:

- Heltec Wifi LoRa 32
- Heltec Wifi LoRa 32 V2

V2 will have “V2” marked on the PCB.

> [@TTN\_44320](#):
>
> - as working board, I select "Tools, Heltec ESP32 Arduino, WifiLora32(V2)

The available Heltec Wifi LoRa 32 boards are listed _exactly_ as follows:

- Heltec Wifi LoRa 32
- Heltec Wifi LoRa 32(V2)

The board you select must match your hardware. Select V2 only if you have a real V2 board.

> [@TTN\_44320](#):
>
> Before going in the modification of this sample program, can you confirm that I’m working on the correct sample program for my module.

As described in the Topic Start `ttn-abp.ino` is the correct example sketch to start with.  
Important is to use the correct pin mappings and corresponding software configuration settings for your board. These are also described in the topic start.

Also note the I2C (SCL, SDA) remarks for V2 in the Topic Start. These are essential for getting the OLED display or other I2C peripherals to work (after you have the basics working).

For the correct format of the LoRaWAN keys and ID’s see:  
[Format of Keys and ID’s for Arduino LMIC libraries [HowTo]](https://www.thethingsnetwork.org/forum/t/format-of-keys-and-ids-for-arduino-lmic-library-howto/28243)

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