At page 56, in TMS23R (TX memory size of socket 2/3 register) section of W5300 datasheet version 1.1.1 the memory sizes of socket 2 and 3 are given like an example below
SOCKET2: 1 KB
But it is written in the datasheet that Total memory size of each socket’s TX Memory should be multiple of 8. Therefore how could we assign 1 and 20 KB which are not multiple of 8?
We recommend that you always refer to the latest version of the datasheet.
The picture below is the latest version datasheet.
The total sum of TSMR0 to 7 must be a multiple of 8.
Socket 0: 4KB
Socket 1: 16KB
Socket 2: 0KB
Socket 3: 7KB
Socket 4: 1KB
Socket 5: 20KB
Socket 6: 12KB
Socket 7: 12KB
4 + 16 + 0 + 7 + 1 + 20 + 12 + 12 = 72
The total sum is 72, a multiple of 8 and does not exceed 128 KB. Therefore, setting is possible.