The W5500 manual specifies that some of the 16-bit registers may have their values changed in the middle of a read operation. In particular, the following registers: Sn_TX_FSR , Sn_RX_RSR. It is recommended that they be read multiple times and compared until two successive reads yield the same value.
Other 16-bit registers, such as : Sn_RX_RD , Sn_RX_WR and other address registers do not have this restriction noted in the user manual.
Can anyone confirm if it is safe to do a single read of these other registers or do they too have to have multiple read-and-compare in order to ensure a correct 16-bit read?
Also, perhaps I have an outdated user manual. Is the read restriction still valid on the Sn_TX_FSR and Sn_RX-RSR registers?