What's the difference between Direct Commands C0 & C1 on the ST25R3916?

[NPeer.11]

C0 and C1 are both stated as "Set Default". Do I need to send both or can it be either, and if it either, why are there 2? The same question can be asked about C2 & C3 as well.

And does any know what RFU means in the ST3916 datasheet?

[Ulysses HERNIOSUS · Accepted solution]

Hi,

you can send either one. You could look at it as one command with LSB being "don't care".

RFU: Reserved for Future Use. Please don't set or clear those bits. Best doing Read-modify-write operations leaving the RFU bits at the read value.

BR, Ulrich