DM9008 查看數據表（PDF） - Davicom Semiconductor, Inc.
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DM9008 Datasheet PDF : 68 Pages
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Receive Status Register (RSR)
This register records the status of the received packet,
including information on errors and the type of address match,
either physical or multicast. The contents of this register are
written to buffer memory by the DMA after reception of a good
packet. If packets with errors are to be saved, the receive
status is written to memory at the head of the erroneous packet
if an erroneous packet is received.
7
6
5
4
DFR
DIS
PHY
MPA
DM9008
ISA/Plug & Play Super Ethernet Contoller
If packets with errors are to be rejected, the RSR will not be
written to memory. The contents will be cleared when the next
packet arrives. CRC errors, frame alignment errors and missed
packets are counted internally by DM9008, which releases the
host from reading the RSR in real time to record errors for
network management functions. The contents of this register
are not specified until after the first reception.
3
2
1
0
FO
FAE
CRC
PRX
Bit
Symbol
Description
D0
PRX
Packet Received Intact: lndicates packet received without error. (Bits CRC, FAE, FO, and
MPA are zero for the received packet.)
D1
CRC
CRC Error: Indicates packet received with CRC error. Increments Tally Counter (CNTR1).
This bit will also be set for Frame Alignment errors
D2
FAE
Frame Alignment Error: Indicates that the incoming packet did not end on a byte boundary and
the CRC did not match at last byte boundary. Increments Tally counter (CNTRO)
D3
FO
FIFO Overrun: This bit is set when the FIFO is not serviced, causing overflow during
reception. Reception of the packet will be aborted
D4
MPA
Missed Packet: Set when packet intended for node cannot be accepted by the DM9008
because of a lack of receive buffers, or when the controller is in monitor mode and did not
buffer the packet to memory. Increments Tally Counter (CNTR2)
D5
PHY
Physical/Multicast Address: Indicates whether received packet had a physical or multicast
address type
0: Physical Address Match
1: Multicast/Broadcast Address Match
D6
DIS
Receiver Disabled: Set when receiver is disabled by entering Monitor mode
Reset when receiver is re-enabled while exiting Monitor mode
D7
DFR
Deferring: Set when the carrier or collision signal is detected by ENC. If the transceiver has
asserted the CD line as a result of the jabber, this bit will stay set, indicating the jabber
condition
Note: The following coding applies to CRC and FAE bits:
FAE
CRC
Type of Error
0
0
No error (Good CRC and <6 Dribble Bits)
0
1
CRC ERROR
1
0
Illegal, will not occur
1
1
Frame Alignment Error and CRC Error
20
Final
Version: DM9008-DS-F02
November 30, 2000
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