W7500x Reference Manual Version1.1.0
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because the bigger data overwrites the previous saved data not yet sent. Therefore, check
before saving the data to the Socket n TX Buffer, and if data is equal or smaller than its
checked size, transmit the data with SEND/SEND_MAC command after saving the data in Socket
n TX Buffer. But, if data is bigger than its checked size, transmit the data after dividing into
the checked size and saving in the Socket n TX Buffer.
If Sn_MR(P[3:0]) is not TCP mode(‘0001’), it is automatically calculated as the difference
between ‘Socket n TX Write Pointer (Sn_TX_WR)’ and ‘Socket n TX Read Pointer (Sn_TX_RD)’.
If Sn_MR(P[3:0]) is TCP mode(‘0001’), it is automatically calculated as the difference
between Sn_TX_WR and the internal ACK pointer which indicates the point of data is received
already by the connected peer.
Ex) In case of 2048(0x0800) in S0_TX_FSR,
0x4600_0204
0x0800
Note) Because this register for representing the size information is 16 bits, it is impossible to
read all bytes at the same time. Before 16 bit-read operation is not completed, the value may
be changed.
Therefore, it is recommended that you read all 16-bits twice or more until getting the same
value.
Sn_TX_RD (Socket n TX Read Pointer Register)
Address Offset : 0x0208
Reset value : 0x0000_0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res
Res
Res
res
res
res
res
res
res
res
res
res
res
res
res
res
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Sn_TXRP[15:0]
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Sn_TX_RD is initialized by OPEN command. However, if Sn_MR(P[3:0]) is TCP mode(‘0001’), it
is re-initialized while connecting with TCP.