W5500 Read/Write Register

Question

Hi! When I was using SPI to read and write the registers of W5500, I found that the first three bytes of data returned for all the read registers were 1, 2, and 3. Is this a normal phenomenon?

Lihan__ · Answer

Hello, I am a software engineer at Wiznet. Yes, that is completely normal. During a read or write operation, the [Address Phase] and [Control Phase] are sent over the MOSI line. At this time, the first three bytes (0x01, 0x02, 0x03) appearing on the MISO line are unrelated to the actual communication and can be ignored. Thank you.