W3100A Datasheet, PDF (30/63 Pages) List of Unclassifed Manufacturers – i2Chip W3100A

the other. The difference between the pointers become the actual FBS (free buffer size). Data is recorded
from Cx_TW_PR according to such size, and when the data recording is complete, Cx_TW_PR is increased
according to the size of the recorded data and executes the send command.
Pointer Management during TCP Transmission
0x2000
CH3
0x1800
CH2
0x1000
CH1
0x0800
CH0
0x0000
2KB allocated
at each channel
0x0800
0x0800
0x0800
Cx_TW_PR and
Cx_TA_PR are equal
(0x00123000
assumed)
Cx_TW_PR is
increased to
0x00123200
(MCU)
Cx_TW_PR
0x0000
Since transmission
memory is 2KB, mask
is 0x000007FF
0x0200
0x0200
Tx
data
Cx_TA_PR
Cx_TA_PR is
increased to
0x0000
0x0000
0x00123200
When MCU records the transmission
(W3100A)
When W3100A
data for transmission and Cx_TW_PR _{completes the}
is increased
transmission
Above diagram illustrates the change in Cx_TW_PR and Cx_TA_PR when actual data transmission is made
after 2KB of transmission memory is set at CH0.
TCP Reception Memory Size Set-up
Receiving memory of W3100A has the same structure of the transmission memory and operated in same
method.
The memory is comprised of 8KB in total, and the size can be assigned for each channel through RMSR (Rx
data Memory Size register). An example of RMSR and each memory size is illustrated in the diagram
below.
When the memory size from channel 0 exceeds 8KB, all ensuing memory is ignored.
Reception Memory Allocation
CH3
0x2000
0x1800
CH2
0x1000
CH1
0x0800
CH0
0x0000
2KB allocated at each channel
RMSR <= 0x55
CH3
0x2000
0x2000
0x1000
CH2
CH1
CH0
0x0800
0x0400
0x0000
1KB, 1KB, 2KB, 4KB allocated
RMSR <= 0x90
CH0
0x1000
0x0000
8KB allocated at channel 0
RMSR <= 0x03
Remaining channels are not used
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