Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
SMSC LAN8720/LAN8720i
45
Revision 1.0 (05-28-09)
DATASHEET
17.6
ALTINT
Alternate Interrupt Mode.
0 = Primary interrupt system enabled (Default).
1 = Alternate interrupt system enabled.
See
Section 5.2, "Interrupt Management," on page 48
.
RW
0
17.5:4
Reserved
Write as 0, ignore on read.
RW
00
17.3
PHYADBP
1 = PHY disregards PHY address in SMI access
write.
RW
0
17.2
Force
Good Link Status
0 = normal operation;
1 = force 100TX- link active;
Note:
This bit should be set only during lab testing
RW
0
17.1
ENERGYON
ENERGYON – indicates whether energy is detected
on the line (see
Section 5.3.5.2, "Energy Detect
); it goes to “0” if no valid
energy is detected within 256ms. Reset to “1” by
hardware reset, unaffected by SW reset.
RO
X
17.0
Reserved
Write as 0. Ignore on read.
RW
0
Table 5.30 Register 18 - Special Modes
ADDRESS
NAME
DESCRIPTION
MODE
DEFAULT
18.15
Reserved
Write as 0, ignore on read.
RW
0
18.14
Reserved
Write as 1, ignore on read.
RW,
NASR
1
18.13:8
Reserved
Write as 0, ignore on read.
RW,
NASR
000000
18.7:5
MODE
Transceiver Mode of operation. Refer to
5.3.9.2, "Mode Bus – MODE[2:0]," on page 53
for
more details.
RW,
NASR
XXX
18.4:0
PHYAD
PHY Address.
The PHY Address is used for the SMI address and for
the initialization of the Cipher (Scrambler) key. Refer
to
Section 5.3.9.1, "Physical Address Bus -
for more details.
RW,
NASR
PHYAD
Table 5.31 Register 26 - Symbol Error Counter
ADDRESS
NAME
DESCRIPTION
MODE
DEFAULT
26.15:0
Sym_Err_Cnt
100Base-TX receiver-based error register that
increments when an invalid code symbol is received
including IDLE symbols. The counter is incremented
only once per packet, even when the received packet
contains more than one symbol error. The 16-bit
register counts up to 65,536 (2
16
) and rolls over to 0
if incremented beyond that value. This register is
cleared on reset, but is not cleared by reading the
register. It does not increment in 10Base-T mode.
RO
0
Table 5.29 Register 17 - Mode Control/Status (continued)
ADDRESS
NAME
DESCRIPTION
MODE
DEFAULT