Beaware of HMC5883 Module

I was toying with cheap GY-721 module. This module is basically a break out for HMC5883L digital compass.

But that is story of the past. Turn out this module is so popular that the Chinese decided to replace the original chip with qmc5883 IC.

Not a new story, they have already clone a lot of STM32 MCU, this IC is a child play for them.

EXCEPT

Their clone is nothing close to the original. The I2C address is different, the register map is also different.

And to make it worse, there are 2 variants of QMC5883: QMC5883L and QMC5883P.

You guess it right, THE VARIANT is nothing close, aparently they come from diffrent vendors.

And when you buy cheap ass GY271 module, it’s a lottery which chip you will get.

I learnt it the hard way today.

HMC5883L datasheet: https://www.farnell.com/datasheets/1683374.pdf

QMC5883L datasheet:

http://wiki.sunfounder.cc/images/7/72/QMC5883L-Datasheet-1.0.pdf

QMC5883P datasheet:

https://www.qstcorp.com/upload/pdf/202202/%EF%BC%88%E5%B7%B2%E4%BC%A0%EF%BC%8913-52-19%20QMC5883P%20Datasheet%20Rev.C(1).pdf