Question: fastMode of the AS5048A

[sylque]

Hi Runger, Would you please explain when the fastMode should be used? What's the benefit of calling readRawAngle() twice? Thanks,

[runger1101001]

Dear sylque,

You can use the fast mode if you want - the difference is the following:

• without fast mode, the sensor is read twice - the second angle read is the current angle, which the result of the first read-angle command
• with fast mode, it reads the sensor only once - this means the angle read is the result of the previous read-angle command, from the last iteration.

So in fast mode, the SPI reads are 2x faster, but the angle result is one iteration old - there is more lag between the angle and the real rotor position.

Which is better really depends on your application, normally I would say not to use fast mode is probably better.

[sylque]

Thanks a lot for the explanation.

I've just had a look at my SPI implementation (ESP32): I'm no expert, but I don't see anything indicating that spi->transfer16() doesn't get the most recent data. So until more tests are done, I will stick to fastMode=true

Thanks again.

--- EDIT: The SPI reading process of the AS5048 indeed involves any reading to be one iteration late, as described on page 11 of the datasheet.

--- EDIT 2: For reference, there might be some additional information in this post and the answer.