3X38FTR Datasheet, PDF (54/64 Pages) Agere Systems – OCTAL-FET (Fast Ethernet Transceiver) for 10Base-T/100Base-TX/FX

3X38FTR 208-Pin SQFP
OCTAL-FET for 10Base-T/100Base-TX/FX
Preliminary Data Sheet
September 2000
Register Information (continued)
Table 34. MR30—Device-Specific Register 3 (10 Mbits/s Control) Bit Descriptions
Bit*
30.15 (Test10TX)
30.14 (RxPLLEn)
30.13 (JAB_DIS)
30.12:7 (UNUSED)
30.6 (LITF_ENH)
30.5 (HBT_EN)
30.4 (ELL_EN)
30.3 (APF_EN)
Type^†
Description
R/W 10Base-T Transmitter Test. When high and 10Base-T is powered up, a con-
tinuous 10 MHz signal (1111) will be transmitted. This is only meant for test-
ing. Default 0.
R/W 10Base-T Low Power Mode Disable. When high, all 10Base-T logic will be
powered up when the link is up. Otherwise, portions of the logic will be pow-
ered down when no data is being received to conserve power. Default is 0.
R/W Jabber Disable. When this bit is 1, disables the jabber function of the
10Base-T receive. Default is 0.
R/W Unused. Read as 0.
R/W Enhanced Link Integrity Test Function. When high, and function is enabled,
it will detect and change speed from 10 Mbits/s to 100 Mbits/s when an instan-
taneous speed change occurs. This is ORed with the LITF_ENH input
(pin T3). Default is 0.
R/W Heartbeat Enable. When this bit is a 1, the heartbeat function will be
enabled. Valid in 10 Mbits/s mode only.
R/W Extended Line Length Enable. When this bit is a 1, the receive squelch lev-
els are reduced from a nominal 435 mV to 350 mV, allowing reception of sig-
nals with a lower amplitude. Valid in 10 Mbits/s mode only.
R/W Autopolarity Function Disable. When this bit is a 0 and the 3X38 is in
10 Mbits/s mode, the autopolarity function will determine if the TP link is wired
with a polarity reversal. Default is 0.
If there is a polarity reversal, the 3X38 will assert the APS bit (register 28, bit
6) and correct the polarity reversal. If this bit is a 1 and the device is in
10 Mbits/s mode, the reversal will not be corrected.
30.2 (RESERVED) R/W Reserved.
30.1 (SERIAL _SEL) R/W Serial Select. When this bit is set to a 1, 10 Mbits/s serial mode will be
selected. When the 3X38 is in 100 Mbits/s mode, this bit will be ignored.
30.0 (ENA_NO_LP) R/W No Link Pulse Mode. Setting this bit to a 1 will allow 10 Mbits/s operation
with link pulses disabled. If the 3X38 is configured for 100 Mbits/s operation,
setting this bit will not affect operation.
* The format for the bit descriptions is as follows: the first number is the register number, the second number is the bit position in the register.
† R = read, W = write.
54
Lucent Technologies Inc.