NXP Semiconductors LPC24XX UM10237 - Manual (Page 235)

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User manual Rev. 04 — 26 August 2009 235 of 792
NXP Semiconductors
UM10237
Chapter 11: LPC24XX Ethernet
Table 11–220 lists the bit definitions of the RSV register.
[1] The EMAC doesn't distinguish the frame type and frame length, so, e.g. when the IP(0x8000) or
ARP(0x0806) packets are received, it compares the frame type with the max length and gives the "Length
out of range" error. In fact, this bit is not an error indication, but simply a statement by the chip regarding the
status of the received frame.
7.2.16 Flow Control Counter Register (FlowControlCounter - 0xFFE0 0170)
The Flow Control Counter register (FlowControlCounter) has an address of 0xFFE0 0170.
Table 11–221 lists the bit definitions of the register.
Table 220. Receive Status Vector register (RSV - address 0xFFE0 0160) bit description
Bit Symbol Function Reset
value
15:0 Received byte count Indicates length of received frame. 0x0
16 Packet previously
ignored Indicates that a packet was dropped. 0
17 RXDV event
previously seen Indicates that the last receive event seen was not long
enough to be a valid packet. 0
18 Carrier event
previously seen Indicates that at some time since the last receive statistics,
a carrier event was detected. 0
19 Receive code
violation Indicates that MII data does not represent a valid receive
code. 0
20 CRC error The attached CRC in the packet did not match the
internally generated CRC. 0
21 Length check error Indicates the frame length field does not match the actual
number of data items and is not a type field. 0
22 Length out of range [1] Indicates that frame type/length field was larger than
1518 bytes. 0
23 Receive OK The packet had valid CRC and no symbol errors. 0
24 Multicast The packet destination was a multicast address. 0
25 Broadcast The packet destination was a broadcast address. 0
26 Dribble Nibble Indicates that after the end of packet another 1-7 bits were
received. A single nibble, called dribble nibble, is formed
but not sent out. 0
27 Control frame The frame was a control frame. 0
28 PAUSE The frame was a control frame with a valid PAUSE
opcode. 0
29 Unsupported Opcode The current frame was recognized as a Control Frame but
contains an unknown opcode.
0
30 VLAN Frame’s length/type field contained 0x8100 which is the
VLAN protocol identifier. 0
31 - Unused 0x0