L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 240

• 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
Appendix A: Registers
Supervisor_Rx_Fifo_Limits
This register is used to define the physical characteristics of the eight supervisor receive FIFOs. These FIFOs
reside within the supervisor’s memory space.
There are eight instances of the three-field record diagrammed in Figure 252. The record at offset zero corre-
sponds to receive FIFO zero.
rx_fifo_start_ptr[31:2] identifies the first physical location of the receive FIFO.
rx_fifo_end_ptr[31:2] identifies the last physical location of the receive FIFO.
rx_fifo_start_ptr[31:2] must be less than rx_fifo_end_ptr[31:2]. These values are established dur-
ing initialization and must be left static during normal operation.
As the supervisor processes each packet, it writes the supervisor memory address of the first 32-bit word of the
received packet’s data structure to rx_fifo_first_ptr[31:2]. The first 32-bit word of each packet is
Supervisor_Rx_Packet.packet_start_ptr[31:2]. rx_fifo_first_ptr[31:2] has the effect of pro-
tecting this packet from being overwritten by the ET4148-50 (the ET4148-50 checks to make sure that there is suf-
ficient room to fit a maximum length packet into a receive FIFO without overwriting the location pointed to by
rx_fifo_first_ptr[31:2]).
There are eight records in this register. Each record corresponds to an individual supervisor receive queue accord-
ing to the following table.
Table 336. Supervisor Receive Queue and Corresponding Register Records
240
REFERENCE
QUEUE
Queue
400
401
402
403
404
405
406
407
SU7
407
SU6
406
SU1
401
(continued)
(continued)
SU0
400
Figure 253. Queue Numbering Scheme
399
QUEUE NUMBERING SCHEME
XG1
...
G = 10/100/1000 Mbits/s PORT
XG = 10 Gbits/s PORT
SU = SUPERVISOR
Agere Systems - Proprietary
392
391
XG0
Register Record
...
384
383
0
1
2
3
4
5
6
7
G47
...
376
15
G1
...
Preliminary Data Sheet
8
7
G0
...
Agere Systems Inc.
0
April 2006