Bits
Bit
Name
Bit
Description
Mode
10 Short Event
o Duration of PHY _RX_DV signal OK. R
1 Duration of
PHY _RX_DV signal was less than
ShortEventMaxTime constant.
11
Alignment Error o Received packet length OK. R
1 Received packet length not an integral number of octets.
12
Bad
FCS o
FCSOK.
R
1 The
FCS value does not match the FCS value calculated by
EMAC.
13
Packet
Too
Long
o Received packet length OK. R
1 Received packet length exceeded maximum
allowed value.
The received packet exceeded the maximum packet length:
• 1518 octets for standard packet
• 1522 octets for VLAN tagged packetData following the maxi-
mum packet length is not transferred to MAL
14
Out of Range Error o Received packet length field value OK. R
1 Received packet length
field value greater than maximum
allowed LLC data size.
The maximum
allowed logical link control (LLC) data size is
greater than
1500 and less than 1536.
15
In
Range Error Refer to Table 19-4 for a description of conditions for activating
R
this status bit.
Table 19-4. In Range Length Error Behavior
for
Various Packet Lengths
Programmed
Length
(Bytes)
Actual
Length
EMAC
Action
Less than 46
Differs from 46 (42 in case of VLAN
In
range length error is activated
(42 if
VLAN Tagged packet)
Tagged packet)
Less than 46
46 (42
in
case of VLAN Tagged
In
range length error is not activated
(42 if
VLAN Tagged packet)
packet)
Greater than or
equal to 46
Equals the length field value
In
range length error is not activated
(42 if
VLAN Tagged packet)
and
less than or equal to 1500
Greater than or equal to 46
Differs from the length field value
In
range length error is activated
(42 if
VLAN Tagged packet)
and
less than or equal to 1500
19.4.3 Early Packet Termination In Receive
Early packet termination occurs when packet reception is aborted by EMAC
befor~
the packet data
transfer to MAL is
completed.
EMAC performs early termination in the following cases.
•
An
overrun occurs in the receive FIFO
•
Packet is too long and the Receive Oversize Packet option is not enabled
(EMACO_RMR[ROP] = 0)
Preliminary
Ethernet Media Access Controller
19-13
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