mauricio-alencar/esp-idf-sx127x

SX1276/77/78/79 Low Power Long Range Transceiver driver for esp-idf

esp-idf-sx127x

SX1276/77/78/79 Low Power Long Range Transceiver driver for esp-idf.

I based on this.

Changes from the original

• Added support for ESP32S2, ESP32S3 and ESP32C3.
• I left the control of CS to the driver.
• Added a sample of ping-pong.
• Added some API functions.

Software requirements

esp-idf v4.4/v5.0.

Installation

git clone https://github.com/nopnop2002/esp-idf-sx127x
cd esp-idf-sx127x/basic/
idf.py set-target {esp32/esp32s2/esp32s3/esp32c3}
idf.py menuconfig
idf.py flash

Note for ESP32C3
For some reason, there are development boards that cannot use GPIO06, GPIO08, GPIO09, GPIO19 for SPI clock pins.
According to the ESP32C3 specifications, these pins can also be used as SPI clocks.
I used a raw ESP-C3-13 to verify that these pins could be used as SPI clocks.

Configuration for Transceiver

SPI BUS selection

The ESP32 series has three SPI BUSs.
SPI1_HOST is used for communication with Flash memory.
You can use SPI2_HOST and SPI3_HOST freely.
When you use SDSPI(SD Card via SPI), SDSPI uses SPI2_HOST BUS.
When using this module at the same time as SDSPI or other SPI device using SPI2_HOST, it needs to be changed to SPI3_HOST.
When you don't use SDSPI, both SPI2_HOST and SPI3_HOST will work.
Previously it was called HSPI_HOST / VSPI_HOST, but now it is called SPI2_HOST / SPI3_HOST.

Wirering

SX127X		ESP32	ESP32-S2/S3	ESP32-C3
RST	--	GPIO16	GPIO38	GPIO8
MISO	--	GPIO19	GPIO37	GPIO4
SCK	--	GPIO18	GPIO36	GPIO5
MOSI	--	GPIO23	GPIO35	GPIO6
NSS	--	GPIO15	GPIO34	GPIO7
GND	--	GND	GND	GND
VCC	--	3.3V	3.3V	3.3V

You can change it to any pin using menuconfig.

Communication with SX126X

LoRa's packet format is strictly specified.
Therefore, if the following three parameters are the same, they can communicate with each other.

• Signal Bandwidth (= BW)
• Error Cording Rate (= CR)
• Spreading Factor (= SF)

Reference

https://github.com/nopnop2002/esp-idf-sx126x