Para entender que esta pasando busca la hoja de datos y mira que indica el error OCF
OCF (Offset Compensation Finished), logic high indicates the finished Offset Compensation Algorithm. If this bit is not set, the data at D11:D0
(likewise M11:M0) may be invalid.
Si el bit no esta en 1, el dato de D11:D0 o sea los 12 bits leídos son inválidos.
Eso es lo que ocurre.
Según la hoja de datos al arrancar OCF se pone en 1.
tPwrUp Power-up time Until status bit OCF = 1 20 ms
Please choose your magnetic strip carefully. The magnetic strips which were sent by www.digikey.ca along with this chip were not working properly. I had to order new magnetic strips from a different company and it worked like a charm. When chip is mounted correctly and magentic strip is parallel to surface of AS5311 chip at a proper distance you will not get these errors "LIN, INC, DEC, COF, OCF". Please read datasheet for more details.