SMSC LAN9311 User Manual
Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Datasheet
Revision 1.4 (08-19-08)
136
SMSC LAN9311/LAN9311i
DATASHEET
9.9.3
RX Status Format
Note:
Though the Host MAC is communicating locally with the switch fabric MAC, the events
described in the RX Status word may still occur.
described in the RX Status word may still occur.
BITS
DESCRIPTION
31
Reserved.
This bit is reserved. Reads 0.
30
Filtering Fail.
When set, this bit indicates that the associated frame failed the address recognizing
filtering.
29:16
Packet Length.
The size, in bytes, of the corresponding received frame.
15
Error Status (ES).
When set this bit indicates that the Host MAC Interface Layer (MIL) has reported
an error. This bit is the Internal logical “or” of bits 11,7,6 and 1.
14
Reserved.
These bits are reserved. Reads 0.
13
Broadcast Frame.
When set, this bit indicates that the received frame has a Broadcast address.
12
Length Error (LE).
When set, this bit indicates that the actual length does not match with the
length/type field of the received frame.
11
Runt Frame.
When set, this bit indicates that frame was prematurely terminated before the collision
window (64 bytes). Runt frames are passed on to the host only if the Pass Bad Frames bit (PASSBAD)
of the
of the
is set.
10
Multicast Frame.
When set, this bit indicates that the received frame has a Multicast address.
9:8
Reserved.
These bits are reserved. Reads 0.
7
Frame Too Long.
When set, this bit indicates that the frame length exceeds the maximum Ethernet
specification of 1518 bytes. This is only a frame too long indication and will not cause the frame
reception to be truncated.
reception to be truncated.
6
Collision Seen.
When set, this bit indicates that the frame has seen a collision after the collision
window. This indicates that a late collision has occurred.
5
Frame Type.
When set, this bit indicates that the frame is an Ethernet-type frame (Length/Type field
in the frame is greater than 1500). When reset, it indicates the incoming frame was an 802.3 type
frame. This bit is not set for Runt frames less than 14 bytes.
frame. This bit is not set for Runt frames less than 14 bytes.
4
Receive Watchdog time-out.
When set, this bit indicates that the incoming frame is greater than
2048 bytes through 2560 bytes, therefore expiring the Receive Watchdog Timer.
3
MII Error.
When set, this bit indicates that a receive error was detected during frame reception.
2
Dribbling Bit.
When set, this bit indicates that the frame contained a non-integer multiple of 8 bits.
This error is reported only if the number of dribbling bits in the last byte is at least 3 in the 10 Mbps
operating mode. This bit will not be set when the collision seen bit[6] is set. If set and the CRC error
bit is [1] reset, then the packet is considered to be valid.
operating mode. This bit will not be set when the collision seen bit[6] is set. If set and the CRC error
bit is [1] reset, then the packet is considered to be valid.
1
CRC Error.
When set, this bit indicates that a CRC error was detected. This bit is also set when the
RX_ER pin is asserted during the reception of a frame even though the CRC may be correct. This bit
is not valid if the received frame is a Runt frame, or a late collision was detected or when the
Watchdog Time-out occurs.
is not valid if the received frame is a Runt frame, or a late collision was detected or when the
Watchdog Time-out occurs.
0
Reserved.
These bits are reserved. Reads 0