DM9008 Ver la hoja de datos (PDF) - Davicom Semiconductor, Inc.
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DM9008 Datasheet PDF : 68 Pages
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Transmit Status Register (TSR)
This register records events that occur on the media during
transmission of a packet. It is cleared when the next
transmission is initiated by the host.
All bits remain low unless the event that corresponds to
7
OWC
6
CDH
5
FU
4
CRS
DM9008
ISA/Plug & Play Super Ethernet Contoller
a particular bit occurs during transmission. Each transmission
should be followed by a read of this register. The contents of
this register are not specified until after the first transmission.
3
ABT
2
COL
1
--
0
PTX
Bit
Symbol
Description
D0
PTX
Packet Transmitted: Indicates transmission without error (no excessive colli-sions or FIFO
underrun) (ABT ="0", FU ="0")
D1
--
Reserved
D2
COL
Transmit Collided: Indicates that transmission collided at least once with another station on
the network. The number of collisions is recorded in the Number of Colli-sions Register (NCR)
D3
ABT
Transmit Aborted: Indicates the DM9008 aborted transmission because of excessive
collisions (total number of transmissions including original transmission attempt equals 16)
D4
CRS
Carrier Sense Lost: This bit is set when carrier is lost during transmission of the packet.
Carrier Sense is monitored from the end of Preamble/Synch until the end of transmission.
Transmission is not aborted on loss of carrier
D5
FU
FIFO Underrun: If the ENC cannot gain access to the bus before the FIF empties, this bit is
set. Transmission of the packet will be aborted
D6
CDH
CD Heartbeat: Failure of the transceiver to transmit a collision signal after transmission of a
packet will set this bit. The Collision Detect (CD) heartbeat signal must commence during the
first 6.4 s of the interframe gap followinga transmission. In certain collisions, the CD
heartbeat bit will be set even though the transceiver is not performing the CD heartbeat test
D7
OWC
Out of Window Collision: Indicates that a collision occurred after a slot time (51.2 s).
Transmissions are rescheduled as in normal collisions
18
Final
Version: DM9008-DS-F02
November 30, 2000
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