3X38FTR Datasheet, PDF (41/64 Pages) Agere Systems – OCTAL-FET (Fast Ethernet Transceiver) for 10Base-T/100Base-TX/FX

Preliminary Data Sheet
September 2000
3X38FTR 208-Pin SQFP
OCTAL-FET for 10Base-T/100Base-TX/FX
Functional Description (continued)
Table 13. Serial LED Pin Descriptions
Signal
SERLEDCLK
SERLEDDATA
SERLEDSTROBE
Type
Output
Output
Output
Description
This is roughly a 1 MHz output clock (25 MHz/16 MHz). All
other serial LED signals change 80 ns—200 ns after the falling
edge of this clock. This clock is generated from LEDCLK.
This is a serial stream, clocked by SERLED clock. The serial
stream contents are discussed below.
This is a strobe, which goes high at the start of each serial
stream. A strobe occurs once every 32 clocks.
Serial Stream Order
Every SERLEDSTROBE indicates a serial LED stream follows. Each serial LED stream consists of the following
components.
Table 14. Serial LED Port Order
Clock #
–1
0
1
2
3
4
5
6
Strobe
1
0
0
0
0
0
0
0
Data
1
Chnl(4) Chnl(3) Chnl(2) Chnl(1) Chnl(0)
Act
Link
Clock #
7
8
9
10
11
12
13
Strobe
0
0
0
0
0
0
0
Data
Speed FullDup Coll
Jabber
APS
RS
XS
Chnl4:0 is the current PHY channel count (0 = channel 0 (A), 1 = channel 1, . . . , 00101 = channel 5 (F)). All other
signals are discussed above. Note that data always goes high when strobe goes high; thus, if a user wishes to
implement a 2-pin interface using just clock and data, this high pulse can be used for synchronization.
The Chnl4:0 will cycle through each of the PHY addresses from 0 to 7 before starting over. Since the LED strobe
occurs once every 32 clocks, there will be 17 clocks between each data burst. Thus, the data burst looks some-
thing like (for PHY channel 0, then channel 1) Figure 14.
Lucent Technologies Inc.
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