NXP Semiconductors LPC1769 - Page 175

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User manual Rev. 3 — 19 December 2013 175 of 841
NXP Semiconductors
UM10360
Chapter 10: LPC176x/5x Ethernet
The StatusInfo word contains flags returned by the MAC and flags generated by the
receive data path reflecting the status of the reception. Table 179
lists the bit definitions in
the StatusInfo word.
Table 178. Receive Status HashCRC Word
Bit Symbol Description
8:0 SAHashCRC Hash CRC calculated from the source address.
15:9 - Unused
24:16 DAHashCRC Hash CRC calculated from the destination address.
31:25 - Unused
Table 179. Receive status information word
Bit Symbol Description
10:0 RxSize The size in bytes of the actual data transferred into one fragment buffer. In
other words, this is the size of the frame or fragment as actually written by
the DMA manager for one descriptor. This may be different from the Size
bits of the Control field in the descriptor that indicate the size of the buffer
allocated by the device driver. Size is -1 encoded e.g. if the buffer has
8 bytes the RxSize value will be 7.
17:11 - Unused
18 ControlFrame Indicates this is a control frame for flow control, either a pause frame or a
frame with an unsupported opcode.
19 VLAN Indicates a VLAN frame.
20 FailFilter Indicates this frame has failed the Rx filter. These frames will not normally
pass to memory. But due to the limitation of the size of the buffer, part of
this frame may already be passed to memory. Once the frame is found to
have failed the Rx filter, the remainder of the frame will be discarded
without being passed to the memory. However, if the PassRxFilter bit in
the Command register is set, the whole frame will be passed to memory.
21 Multicast Set when a multicast frame is received.
22 Broadcast Set when a broadcast frame is received.
23 CRCError The received frame had a CRC error.
24 SymbolError The PHY reports a bit error over the PHY interface during reception.
25 LengthError The frame length field value in the frame specifies a valid length, but does
not match the actual data length.
26 RangeError
[1]
The received packet exceeds the maximum packet size.
27 AlignmentError An alignment error is flagged when dribble bits are detected and also a
CRC error is detected. This is in accordance with IEEE std. 802.3/clause
4.3.2.
28 Overrun Receive overrun. The adapter can not accept the data stream.
29 NoDescriptor No new Rx descriptor is available and the frame is too long for the buffer
size in the current receive descriptor.
30 LastFlag When set to 1, indicates this descriptor is for the last fragment of a frame.
If the frame consists of a single fragment, this bit is also set to 1.
31 Error An error occurred during reception of this frame. This is a logical OR of
AlignmentError, RangeError, LengthError, SymbolError, CRCError, and
Overrun.