Project Description

Introduction

I got some LoRa modules with SPI communication interface. One of the options it would have been to connect them to my Raspberry Pi. But, I didn’t really liked the idea because I already had some stuff connected to my Raspberry Pi, and this starts getting unmanageable.

So, I decided to create a LoRa-to-Ethernet gateway that can be connected directly to a home router. The WIZ750SR module with its Ethernet interface and Cortex-M0 SoC was a great candidate to implement such a device.

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The LoRa modules

I used two 433 MHz modules purchased from AliExpress. The boards are powered by the Semtech SX1278 chip.

After attaching a ribbon cable to the board and some pin headers to the other end the boards were ready for testing.

The Lora Module is connected to the Arduino boards as follows:

  • VCC – 3.3V,
  • GND – GND
  • SCK – SCK
  • MISO – MISO
  • MOSI – MOSI
  • NSS – pin 10
  • NRESET – pin 9
  • DIO0 – pin 2

The WIZ750SR module and the W7500P SoC

The WIZ750SR is a Serial-to-Ethernet module from WIZnet:

The board allows controlling serial devices over an Ethernet network, but with a custom software is capable of much more than that.

The board is powered by the W7500P SoC. The W7500P, according to its datasheet, uses an ARM Cortex-M0 core and along UART also supports I2C, SPI and standard GPIO.

The SPI1 unit of the W7500P uses the same pins as the UART0 module (CTS = PA_11, RTS = PA_12, TXD = PA_13, RXD = PA_14) used in WIZ750SR module. This means that after some tweaking in the software we can use those pins for SPI communication.

Along with SPI pins, we need 3 more pins. We can use the A, B, C pins of the WIZ750SR module, which are standard GPIO pins (PC_13, PC_12 and PC_9).

After successfully getting through the Getting Started Guide, I started implementing the LoRa related functionality.

Original Source : https://www.hackster.io/bluetiger9/lora-to-ethernet-gateway-ff9684

Tags : 201806, W7500P, WIZ750SR, LoRa, Gateway

Writer : Attila Tőkés  (https://www.hackster.io/bluetiger9)