SMSC LAN1198 Manual De Usuario

Descargar
Página de 45
LAN9118 Family Programmer Reference Guide
SMSC AN 12.12
33
Revision 1.0 (12-14-09)
APPLICATION NOTE
 
6.5.1   Transmit Command Words for 
Note: The use of the First Segment and Last Segment flags in the example detailing the head,
middle, and tail of the chained transfer.  Also see how the Buffer Size is unique for each
transfer, while the Packet Length reflects the total packet size.  Finally, the Packet Tag must
be identical for correct operation.  The new sequence of 3 data transfers looks like this:
Table 6.6  TX_CMD_A for Segment 1
3
1
3
0
2
9
2
8
2
7
2
6
BUFFER 
END 
ALIGNME
NT
2
3
2
2
2
1
DATA 
START 
OFFSET
1
5
1
4
FIRST 
SEGMENT
LAST 
SEGME
NT
1
1
BUFFER 
SIZE
0x0
0x3
1
0
0x1d
Table 6.7  TX_CMD_B for Segment 1
PACKET TAG
15
14
13
12
11
PACKET 
LENGTH
0x5678
0x4e
Table 6.8  TX_CMD_A for Segment 2
3
1
3
0
2
9
2
8
2
7
2
6
BUFFER 
END 
ALIGNMENT
2
3
2
2
2
1
DATA 
START 
OFFSET
1
5
1
4
FIRST 
SEGMENT
LAST 
SEGMENT
1
1
BUFFER SIZE
0x0
0x0
0
0
0x20
Table 6.9  TX_CMD_B for Segment 2
PACKET TAG
15
14
13
12
11
PACKET 
LENGTH
0x5678
0x4e
Table 6.10  TX_CMD_A for Segment 3
3
1
3
0
2
9
2
8
2
7
2
6
BUFFER 
END 
ALIGNMENT
2
3
2
2
2
1
DATA 
START 
OFFSET
1
5
1
4
FIRST 
SEGMENT
LAST 
SEGMENT
1
1
BUFFER SIZE
0x0
0x0
0
1
0x11
Table 6.11  TX_CMD_B for Segment 3
PACKET TAG
15
14
13
12
11
PACKET 
LENGTH
0x5678
0x4e