3X38FTR Datasheet, PDF (39/64 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)
The autonegotiation function within the 3X38 can be
controlled either by internal register access or by the
use of configuration pins. At powerup and at device
reset, the configuration pins are sampled. If disabled,
autonegotiation will not occur until software enables bit
12 in register 0. If autonegotiation is enabled, the nego-
tiation process will commence immediately.
When autonegotiation is enabled, the 3X38 transmits
the abilities programmed into the autonegotiation
advertisement register at address 04h via FLP bursts.
Any combination of 10 Mbits/s, 100 Mbits/s, half-
duplex, and full-duplex modes may be selected. Auto-
negotiation controls the exchange of configuration
information. Upon successful autonegotiation, the abili-
ties reported by the link partner are stored in the auto-
negotiation link partner ability register at address 5.
The contents of the autonegotiation link partner ability
register are used to automatically configure to the
highest-performance protocol between the local and
far-end nodes. Software can determine which mode
has been configured by autonegotiation by comparing
the contents of register 04h and 05h and then selecting
the technology whose bit is set in both registers of high-
est priority relative to the following list:
1. 100Base-TX full duplex (highest priority)
2. 100Base-TX half duplex
3. 10Base-T full duplex
4. 10Base-T half duplex (lowest priority)
The basic mode control register at address 00 provides
control of enabling, disabling, and restarting of the
autonegotiation function. When autonegotiation is dis-
abled, the speed selection bit (bit 13) controls switching
between 10 Mbits/s or 100 Mbits/s operation, while the
duplex mode bit (bit 8) controls switching between full-
duplex operation and half-duplex operation. The speed
selection and duplex mode bits have no effect on the
mode of operation when the autonegotiation enable bit
(bit 12) is set.
The basic mode status register at address 01h indi-
cates the set of available abilities for technology types
(bits 15 to 11), autonegotiation ability (bit 3), and
extended register capability (bit 0). These bits are hard-
wired to indicate the full functionality of the 3X38. The
BMSR also provides status on:
1. Whether autonegotiation is complete (bit 5).
2. Whether the link partner is advertising that a remote
fault has occurred (bit 4).
3. Whether a valid link has been established (bit 2).
The autonegotiation advertisement register at address
04h indicates the autonegotiation abilities to be adver-
tised by the 3X38. All available abilities are transmitted
by default, but any ability can be suppressed by writing
to this register or configuring external pins.
The autonegotiation link partner ability register at
address 05h indicates the abilities of the link partner as
indicated by autonegotiation communication. The con-
tents of this register are considered valid when the
autonegotiation complete bit (bit 5, register address
01h) is set.
The 3X38 contains an enhanced autonegotiation func-
tion that can detect instantaneous speed changes from
10 Mbits/s to 100 Mbits/s. This function can be acti-
vated by the LITF_EN input pin, or by setting register
30, bit 6 high. Register 31 provides enhanced autone-
gotiation status information for debugging purposes.
LED Operational Modes
The 3X38 provides three basic LED output modes of
operation: parallel mode, serial mode, and bicolor LED
mode. The parallel mode provides four LED output sig-
nals for each of the eight channels (32 signals total):
activity, link, speed, and full duplex. The serial mode
multiplexes all eight channels LED status information
onto one single serial output stream. The single data
stream, SERDATA, is accompanied with a serial clock,
SERCLK, and a serial LED strobe, SERSTROBE
(three signals total).
The bicolor LED mode provides two LED output sig-
nals, BIACTLED [7:0] and BILINKLED [7:0], for each of
the eight channels (16 signals total). These two outputs
are intended to drive a bicolor LED, packaged in one
single LED package. This reduces the total number of
LED packages to one per channel.
Lucent Technologies Inc.
39