In your datasheet MFRC522 Standard performance MIFARE and NTAG frontend you have referred to Table 10. Selectable UART transfer speeds with Accuracy with positive and negative values with only one remark saying The resulting transfer speed error is less than 1.5 % for all described transfer speeds. what is meant by +/- mark on the values and what is btter speed to choose if both fluctuate from - to + values around 9.6 kBd what is the law that our calculation is based on for - and + value I mean an error is an error? i.e. a lost bit, or not? I just do not understand - and + values???
Dear MNF SOFT,
By this it does not mean a los of a bit it means that the speed may vary +/- 1.5 % so there is not way to guarantee any device that works perfeclty due to all of the factors that can affect the speed, so there is an error margin that we provide that we guarantee that the speed may fluctuate between +/- 1.5 %. I think the default value of the UART is ok but this will depend on your side and application to fulfill the need of your project.
Have a great day !
BR
Jonathan