
158
Agere Systems Inc.
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
Data Sheet
July 2001
12 Ethernet 10/100 PHY(s)
(continued)
12.5.18 MR31 Device-Specific Register 4 (Quick Status) Bit Description
Bit #
4
Name
ELL_EN
Type
R/W
Description
Extended line length enable.
If 1, the receive squelch levels are reduced from a nominal 435 mV to
350 mV, allowing reception of signals with a lower amplitude.
Valid in 10 Mbits/s mode only.
Autopolarity function disable.
3
APF_EN
R/W
If 0, and the 10/100 Ethernet transceiver macrocell is in 10 Mbits/s mode,
the autopolarity function will determine if the
TP
link is wired with a polarity
reversal.
If 1, and the device is in 10 Mbits/s mode, the reversal will not be cor-
rected.
Reserved.
Serial select.
If set to a 1, the 10 Mbits/s serial mode will be selected.
When the 10/100 Ethernet transceiver macrocell is in 100 Mbits/s mode,
this bit will be ignored. This bit should be set to one when the repeater is
used, and cleared to zero when the repeater is bypassed.
No link pulse mode.
Setting this bit to a 1 will allow 10 Mbits/s operation
with link pulses disabled. If the 10/100 Ethernet transceiver macrocell is
configured for 100 Mbits/s operation, setting this bit will not affect opera-
tion.
2
1
RESERVED
SERIAL _SEL
R/W
R/W
0
ENA_NO_LP
R/W
Table 143. MR31 Device-Specific Register 4 (Quick Status) Bit Description
Bit #
15
Name
ERROR
Type
R
Description
Receiver error.
If 1, it indicates that a receive error has been detected. This bit is
valid in 100 Mbits/s only. This bit will remain set until cleared by read-
ing the register.
Default = 0.
False carrier.
When
INT_CONF
is set to 0 and this bit is a 1, it indi-
cates that the carrier detect state machine has found a false carrier.
This bit is valid in 100 Mbits/s only. This bit will remain set until
cleared by reading the register.
14
RXERR_ST
LINK_STAT_CHANGE
R
Default = 0.
Link status change.
When
INT_CONF
is set to a 1, this bit is rede-
fined to become the
LINK_STAT_CHANGE
bit and goes high when-
ever there is a change in link status (
LSTAT_OK
changes state).
Remote fault.
13
REM_FLT
R
If 1, it indicates that a remote fault has been detected. This bit will
remain set until cleared by reading the register.
Default = 0.
Table 142. MR30 Device-Specific Register 3 (10 Mbits/s Control) Bit Description
(continued)