RAK5801 access to MCU

[crmrosa (claudio roberto machado da rosa)]

Please include the following information, in order for us to help you as effectively as possible.

• What product do you wish to discuss? RAK4631
• What firmware are you using? Arduino BSP
• What firmware version? Can it be obtained with AT+VER=?
• Computer OS? (MacOS, Linux, Windows) Windows
• What Computer OS version? Windows 11

Good afternoon,

I would like to understand better how is the RAK5801 communication with the nRF52840. I was looking in the spreadsheet Wisblock-IO-Pin-Mapper.xlsx(screenshot below). I saw that RAK5801 is connect at pin A0=>P0.04, A1=>P0.31, IO1=>P0.17, I2C_SDA=>P0.13 and I2C_SCL=>P0.14

In the example Hydraulic Pressure Monitoring :

/**
 * @file Hydraulic_Pressure_Monitoring.ino
 * @author rakwireless.com
 * @brief This sketch demonstrate reading data from a P300 hydraulic pressure sensor
 *    and send the data to lora gateway.
 * @version 0.1
 * @date 2020-07-28 
 * @copyright Copyright (c) 2020
 */

#include <Arduino.h>
#include <LoRaWan-RAK4630.h> //http://librarymanager/All#SX126x
#include <SPI.h>

void setup()
{
	pinMode(LED_BUILTIN, OUTPUT);
	digitalWrite(LED_BUILTIN, LOW);

	/* WisBLOCK 5801 Power On */
	pinMode(WB_IO1, OUTPUT);
	digitalWrite(WB_IO1, HIGH);
	/* WisBLOCK 5801 Power On */

1. Why the code has “#include <SPI.h>”, if RAK5801 is not using SPI, or I am wrong ?
2. Why RAK5801 is connect to I2C if it is not being used? Could I used I2C instead of a direct pin WB_IO1?

Regards,

Cláudio

[carlrowan]

Hi @crmrosa ,

To answer your question.

1. SPI is used to communicate with the Semtech LoRa transceiver.
2. I2C is there to allow you to attach external sensors/peripherals that that is based on I2C. You can use the I2C pins as you see fit in your application.

[crmrosa (claudio roberto machado da rosa)]

Hi @carlrowan ,

The SPI, it is correct, I forgot about the SX1262.

About I2C, I know the in my environment, RAK1904/RAK1906/RAK/RAK15004/RAK12500 are using I2C, but I didn´t see in the code any mention about RAK5801 I2C address, but it is connect with I2C. Why?

[beegee (Bernd Giesecke)]

The RAK5801 does not have any I2C device on it, but it exposes the I2C bus on its connector.
I guess that’s the only reason why it is in the example codes.

[carlrowan]

Hi @crmrosa ,

As Bernd said, it is only a connector.

Good use case is for example you need to integrated a temp-humidity probe sensors via I2C to WisBlock, you can easily attach such external sensor probes.

[crmrosa (claudio roberto machado da rosa)]

Thank you, @carlrowan and @beegee .

Claudio