LAN91C100FD_0601 Datasheet, PDF (24/78 Pages) SMSC Corporation – FEAST Fast Ethernet Controller with Full Duplex Capability

FEAST Fast Ethernet Controller with Full Duplex Capability
LOOP - Loopback. General purpose output port used to control the LBK pin. Typically used to put the PHY
chip in loopback mode.
TXENA - Transmit enabled when set. Transmit is disabled if clear. When the bit is cleared the
LAN91C100FD will complete the current transmission before stopping. When stopping due to an error, this
bit is automatically cleared.
BANK 0
OFFSET
2
NAME
EPH STATUS REGISTER
TYPE
READ ONLY
SYMBOL
EPHSR
This register stores the status of the last transmitted frame. This register value, upon individual transmit
packet completion, is stored as the first word in the memory area allocated to the packet. Packet interrupt
processing should use the copy in memory as the register itself will be updated by subsequent packet
transmissions. The register can be used for real time values (like TXENA and LINK OK). If TXENA is
cleared the register holds the last packet completion status.
HIGH
BYTE
LOW
BYTE
TX
UNRN
0
TX
DEFR
0
LINK_
OK
-nLNK
pin
LTX
BRD
0
0
0
SQET
0
CTR
_ROL
0
16COL
0
EXC
_DEF
0
LTX
MULT
0
LOST
CARR
0
MUL
COL
0
LATCOL
0
0
SNGL
COL
0
0
TX_SUC
0
TXUNRN - Transmit Under Run. Set if under run occurs, it also clears TXENA bit in TCR. Cleared by
setting TXENA high. This bit may only be set if early TX is being used.
LINK_OK - General purpose input port driven by nLNK pin inverted. Typically used for Link Test. A
transition on the value of this bit generates an interrupt.
CTR_ROL - Counter Roll Over. When set one or more 4 bit counters have reached maximum count (15).
Cleared by reading the ECR register.
EXC_DEF - Excessive Deferral. When set last/ current transmit was deferred for more than 1518 * 2 byte
times. Cleared at the end of every packet sent.
LOST_CARR - Lost Carrier Sense. When set indicates that Carrier Sense was not present at end of
preamble. Valid only if MON_CSN is enabled. This condition causes TXENA bit in TCR to be reset.
Cleared by setting TXENA bit in TCR.
LATCOL - Late collision detected on last transmit frame. If set a late collision was detected (later than 64
byte times into the frame). When detected the transmitter jams and turns itself off clearing the TXENA bit
in TCR. Cleared by setting TXENA in TCR.
TX_DEFR - Transmit Deferred. When set, carrier was detected during the first 6.4 μs of the inter frame
gap. Cleared at the end of every packet sent.
LTX_BRD - Last transmit frame was a broadcast. Set if frame was broadcast. Cleared at the start of every
transmit frame.
SQET - Signal Quality Error Test. In MII, SQET bit is always set after first transmit, except if SWFDUP=1.
As a consequence, the STP_SQET bit in the TCR register cannot be set as it will always result in transmit
fatal error. In non-MII systems, the transmitter opens a 1.6 μs window 0.8 μs after transmission is
completed and the receiver returns inactive. During this window, the transmitter expects to see the SQET
signal from the transceiver. The absence of this signal is a 'Signal Quality Error' and is reported in this
Rev. 01-20-06
Page 24
DATASHEET
SMSC DS – LAN91C100FD Rev. D