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sqrtmo / GY-85-arduino

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Use uint8_t instead of int #4

Open chevdor opened 5 years ago

chevdor commented 5 years ago

Nice work on this lib, thanks for sharing.

In Arduinos such Uno, etc.. an int is 8 bits. Life is great. Now using a non 8 bit arch such as an ESP32, it starts getting messy.

I think that switching from int to uint8_t would stay closer to what the lib should do.

sqrtmo commented 5 years ago

Thanks for pointing that out. Was long time ago since I wrote that. I should find some time to update the whole code. Till that will fix the types.

chevdor commented 5 years ago

No worries and thanks for sharing in the first place.

I can tell you I spotted another issue (lost hairs on that one :)) This is an issue that I guess you cannot run into with an 8bit MCU such as the ATmega328 but you will if you use something like an ESP32.

If you happen to test, I suggest testing on the temperature, if you get 250 °C, you know you lost :)

An important fix is to cast to (uint16_t) in locations such as: https://github.com/sqrtmo/GY-85-arduino/blob/master/GY_85.cpp#L157

Then suddenly, all the values match what an Arduino would output.

chevdor commented 5 years ago

So around L157, you should find:

 axis[0] = (int16_t)((int)(buff[4] << 8) | buff[5]) - g_offx;
    axis[1] = (int16_t)((buff[2] << 8) | buff[3]) - g_offy;
    axis[2] = (int16_t)((buff[6] << 8) | buff[7]) - g_offz;
    axis[3] = (int16_t)((buff[0] << 8) | buff[1]);            // temperature

NOTE: I did not check yet if this fixes breaks it on 8 bits MCUs.