L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 50

• Manufacturer Part Number: L-ET4148-50C-DB
• Manufacturer: LSI

Specifications of L-ET4148-50C-DB

• Lead Free Status / RoHS Status: Supplier Unconfirmed

ET4148-50
Single-Chip 48 x 1 Gbit/s + 2 x 10 Gbits/s Layer 2+ Ethernet Switch
Data Structures
Supervisor_Tx_Descriptor
Description: A list of descriptors of supervisor transmit packet segments.
Table 11. Supervisor_Tx_Descriptor Register Parameters
Table 12. Supervisor_Tx_Descriptor Field Parameters
This data structure is a list of descriptors of packet segments. Each packet segment requires its own descriptor.
The descriptors are processed in the order in which they are encountered in Supervisor_Tx_Descriptor.
Each packet requires a Supervisor_Tx_Descriptor structure with at least one record.
Transmit packet processing is terminated upon the completion of processing of the record whose last bit is
asserted.
tx_segment_ptr[31:0] is able to address segments on any arbitrary byte boundary. Each segment may also
be of any arbitrary byte length. The ET4148-50 ensures that packet segments are stitched together correctly.
The physical extent of Supervisor_Tx_Descriptor is defined by Supervisor_Tx_Fifo_Limits_{0..1}.
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Base Address
Structure Size
Structure Instances
Structure Spacing
tx_segment_ptr[31:0]
last
indicate
tx_segment_length[13:0]
0
4
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
0
1
Field Name
Parameter
2
3
4
5
(continued)
6
7
Figure 24. Supervisor_Tx_Descriptor Data Structure
8
9
Supervisor_Tx_Fifo_{0..1}.tx_descriptor_ptr[31:2]
Variable
Variable
Variable
Offset = 4.18
Mode = R/W
Mode = R/W
Mode = R/W
Mode = R/W
Parameters
Offset = 0.0
Offset = 4.0
Offset = 4.1
10
11
Agere Systems - Proprietary
12
tx_segment_ptr[31:0]
13
14
15
A pointer to a supervisor transmit packet segment.
When asserted, this descriptor is a packet’s last descriptor.
When asserted by the supervisor, the tx_packet indication is
asserted in Supervisor_Ind upon completion of the trans-
fer of the corresponding transmit packet segment.
The size of a packet segment.
16
17
18
Value
19
20
21
22
tx_segment_length[13:0]
Description
23
8
24
7
25
6
Preliminary Data Sheet
26
5
27
4
28
3
Agere Systems Inc.
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2
30
1
April 2006
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0