L-ET4148-50C-DB LSI, L-ET4148-50C-DB Datasheet - Page 186

• 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
Packet_Buffer_Shaper_Delta_Even
Description: These values determine a shaper’s target byte rate.
Table 253. Packet_Buffer_Shaper_Delta_Even Register Parameters
Table 254. Packet_Buffer_Shaper_Delta_Even Field Parameters
On a periodic basis, the value of shaper_delta[11:4] is added to its corresponding
Packet_Buffer_Shaper_Accumulator register field. The period of these applications of credit is derived from
the system clock and is dependent on the bit rate of the associated interface. If a period of p is assumed for a
10 Gbits/s Ethernet port, then 10p is used for 1 Gbit/s, 100p for 100 Mbits/s, and 1000p for 10 Mbits/s. The nominal
value for p is 1.28 µs, or 781,250 credits per second.
When updated 781,250 times per second for a 10 Gbits/s port, a shaper_delta[11:0] value of 16
(shaper_delta[11:4] = 0x1) results in a transmit byte rate of 12.5 Mbytes/s; or 100 Mbits/s. This is 1% of 10 Gbits/s.
A shaper_delta[11:0] value of 1,600 results in a transmit byte rate of 1,250 Mbytes/s, or 10 Gbits/s. This is, of
course, 100% of the interface’s rated speed.
For lower-speed interfaces, the credit application rate is reduced proportionately. Therefore, the same values of 16
and 1,600 can be used in shaper_delta[11:0] as the minimum and maximum data rates.
Port speed is indicated by values set in Packet_Buffer_Port_Speed by the supervisor.
186
REFERENCE
Base Address
Register Size
Register Instances
Register Spacing
Record Size
Record Instances
Record Spacing
shaper_delta[11:4]
QUEUE
0
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9
0
Field Name
Parameter
SU7
407
1
SU6
406
2
3
4
Figure 183. Packet_Buffer_Shaper_Delta_Even Register Diagram
5
SU1
401
6
SU0
400
7
(continued)
399
8
XG1
Figure 184. Queue Numbering Scheme
Instances = 1
Offset = 0.20
...
9
Mode = R/W
Parameters
10
392
Agere Systems - Proprietary
11
391
0x000c_b000
12
QUEUE NUMBERING SCHEME
G = 10/100/1000 Mbits/s PORT
XG0
XG = 10 Gbits/s PORT
SU = SUPERVISOR
...
13
Value
816
204
NA
1
4
4
14
384
15
383
The credit that is periodically added to an accumulator.
16
G47
...
17
376
18
19
20
21
shaper_delta[11:4]
22
15
Description
23
8
G1
...
24
7
8
25
6
Preliminary Data Sheet
7
26
5
G0
27
...
4
28
Agere Systems Inc.
3
0
0
29
2
0
30
1
0
April 2006
31
0
0