Boards and Pins

These boards have been successfully tested with ttn-esp32:

• TTGO LoRa32 v1
• TTGO LoRa32 v2
• TTGO LoRa32 v2.1
• Heltec LoRa 32
• Adafruit RFM95 breakout board
• Hope RFM95W module

The pin configuration of each board is shown for each one.

TTGO LoRa32 868MHz v1 (SX1276, with and without display)

Version 1 boards can be recognized by the metal WiFi antenna along the pins.

Pin configuration

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       14
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33

menuconfig

The default TTN values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)

However, these boards usually have a XTAL frequency of 26 MHz (instead of the default 40 MHz). The correct XTAL frequency can be found on the quartz on the back of the board between the pins 19 and SRT (a magnifying glass will be helpful). The XTAL frequency needs to be set with menuconfig at Component config / ESP-32 specific / Main XTAL frequency

TTGO LoRa32 868MHz v2 (SX1276, with display)

Version 2 boards can be recognized by the improved placement of the metal WiFi antenna on the short side of the board while still retaining the tiny U.FL/IPEX connector.

Pin configuration

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       TTN_NOT_CONNECTED
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33 †

† DIO1 of SX127x must be manually wired to a free GPIO of the ESP32. Otherwise it will not work. In the above configuration, GPIO 33 has been chosen. See this LilyGO issue for a pinout of the board. DIO1 (labelled LoRa_DIO1) and GPIOs can be found as pin holes (or as pins if pin headers have been soldered) on the long sides of the board.

menuconfig

The default values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)

TTGO LoRa32 868MHz v2.1 (SX1276, with display)

The v2.1 boards can be recognized by the bigger SMA antenna connector (instead of the tiny U.FL/IPEX connector).

The below information has been verified with a board that was marked: T3_V1.5 20180523. Other versions of the v2.1 boards seem to exist. Also note that the RST pin of the shielded LoRa module (third one from top left) is not connected.

Pin configuration

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       TTN_NOT_CONNECTED
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33

menuconfig

The default values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)

heltec LoRa 32 868MHz (SX1276, with display)

Pin configuration

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       14
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33

menuconfig

The default TTN values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)

However, these boards usually have a XTAL frequency of 26 MHz (instead of the default 40 MHz). The correct XTAL frequency can be found on the quartz on the back of the board between the pins 22 and RST (a magnifying glass will be helpful). The XTAL frequency needs to be set with menuconfig at Component config / ESP-32 specific / Main XTAL frequency

Adafruit RFM95W 868 MHz breakout board (SX1276)

It's a breakout board with an RFM95W module:

PIN configuration

As the board needs to be wired up, many different pin configurations are possible. This one has been successfully tested:

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       14
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33

menuconfig

The default TTN values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)

Hope RFM95W 868 MHz module (SX1276)

It's an inexpensive module for the SX1276 chip.

PIN configuration

As the module needs to be wired up, different pin configurations are possible. This one has been successfully tested:

#define TTN_SPI_HOST      HSPI_HOST
#define TTN_SPI_DMA_CHAN  1
#define TTN_PIN_SPI_SCLK  5
#define TTN_PIN_SPI_MOSI  27
#define TTN_PIN_SPI_MISO  19
#define TTN_PIN_NSS       18
#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
#define TTN_PIN_RST       14
#define TTN_PIN_DIO0      26
#define TTN_PIN_DIO1      33

menuconfig

The default TTN values should work fine:

• TTN radio chip: Semtech SX1276 / SX1277 / SX1278 / SX1279
• SPI frequency: 10,000,000 (10 MHz)