Datasheet

W5500 Datasheet Version1.0.9 31 / 66
3.3 Memory
W5500 has one 16KB TX memory for Socket n TX Buffer Blocks and one 16KB RX
memory for Socket n RX buffer Blocks.
16KB TX memory is initially allocated in 2KB size for each Socket TX Buffer Block (2KB
X 8 = 16KB). The initial allocated 2KB size of Socket n TX Buffer can be re-allocated by
using ‘Socket n TX Buffer Size Register (Sn_TXBUF_SIZE)’.
Once all Sn_TXBUF_SIZE registers have been configured, Socket TX Buffer is allocated
with the configured size of 16KB TX Memory and is assigned sequentially from Socket
0 to Socket 7. Its physical memory address is automatically determined in 16KB TX
memory. Therefore, the total sum of Sn_TXBUF_SIZE should be not exceed 16 in case
of error in data transmission.
The 16KB RX memory allocation method is the same as the 16KB TX memory
allocation method. 16KB RX memory is initially allocated into 2KB size for each Socket
RX Buffer Block (2KB X 8 = 16KB). The initial allocated 2KB size of Socket n RX Buffer
can be re-allocated by using ‘Socket n RX Buffer Size Register (Sn_RXBUF_SIZE)’.
When all Sn_RXBUF_SIZE registers have been configured, the Socket RX Buffer is
allocated with the configured size in 16KB RX Memory and is assigned sequentially from
Socket 0 to Socket 7. The physical memory address of the Socket RX Buffer is
automatically determined in 16KB RX memory. Therefore, the total sum of
Sn_RXBUF_SIZE should not exceed 16, data reception error will occur if exceeded.
For 16KB TX/RX memory allocation, refer to Sn_TXBUF_SIZE & Sn_RXBUF_SIZE in
‘Chapter 4.2’.
The Socket n TX Buffer Block allocated in 16KB TX memory is buffer for saving data
to be transmitted by host. The 16bits Offset Address of Socket n TX Buffer Block has
64KB address space ranged from 0x0000 to 0xFFFF, and it is configured with reference
to ‘Socket n TX Write Pointer Register (Sn_TX_WR)’ & ‘Socket n TX Read Pointer
Register(Sn_RX_RD)’. However, the 16bits Offset Address automatically converts into
the physical address to be accessible in 16KB TX memory such as Figure 20. Refer to
‘Chapter 4.2’ for Sn_TX_WR & Sn_TX_RD.
The Socket n RX Buffer Block allocated in 16KB RX memory is buffer for saving the
received data through the Ethernet. The 16bits Offset Address of Socket n RX Buffer
Block has 64KB address space ranged from 0x0000 to 0xFFFF, and it is configured with
reference to ‘Socket n RX RD Pointer Register (Sn_RX_RD)’ & ‘Socket n RX Write Pointer
Register (Sn_RX_WR)’. However, the 16bits Offset Address automatically converts into
the physical address to be accessible in 16KB RX memory such as Figure 20. Refer to
‘Chapter 4.2’ for Sn_RX_RD & Sn_RX_WR.