I2C HMC5983 communication issue

Question

I have a really weird problem, when I run the exmple wire (I2C) scanner from Arduino, I get:

I2C Scanner Scanning... I2C device found at address 0x1E ! done

However when I try directly to the 0x1E I get the following error code 2:

received NACK on transmit of address.

Below is my code that i did only modify the example code:

#include <Wire.h>

void setup() {
  Wire.begin();

  Serial.begin(9600);
  while (!Serial); // Leonardo: wait for Serial Monitor
  Serial.println("\nI2C Scanner");
}

void loop() {

  Serial.println("Scanning...");

  byte address = 0x1E;

  Wire.beginTransmission(address);
  byte error = Wire.endTransmission();

  if (error == 0) {
    Serial.print("I2C device found at address 0x1E");
  } else if (error == 1) {
      Serial.print("data too long to fit in transmit buffer.");
  }
  else if (error == 2) {
      Serial.print("received NACK on transmit of address.");
  }
  else if (error == 3) {
      Serial.print("received NACK on transmit of data.");
  }
  else if (error == 4) {
      Serial.print("Unknown error at address 0x");
  }

  delay(5000); // Wait 5 seconds for next scan
}

Answer 1

There are certain situations where the device can send a nack after a valid address is sent - search "received NACK on transmit of address". Nothing I read applies specifically to your situation.

I see nothing in the HMC5983 datasheet (https://www.farnell.com/datasheets/1509871.pdf?_ga=2.219060057.1318745487.1555987311-293789508.1555987311) that could account for what you are seeing.

I don't have an HMC5983 on a GY282 module (you mentioned the module in a different forum) as you do, but I have it's predecessor, HMC5883 which I think is largely comparable, but slower.

I tested your code and I DID NOT get the NACK error - it simply reported finding the the device.

Then, I tested the leanest HMC5883 code I could find and I saw systematic output, which changed as I moved the device.

Then I tested similar code for the HMC5983 (see https://wiki.eprolabs.com/index.php?title=GY-282_HMC5983_Module#Hardware_Connections). That code worked on my slower HMC5883 board (e.g., systematic output).

I suggest the following - double check the solder blobs on the board to make sure I2C/SPI is jumpered properly - also the 3v3 CS blobs - a picture would be helpful.

I would also suggest that you try to run the HMC5983 code that I linked and see what you get.

Hope it helps.