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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
134 of 808
NXP Semiconductors
UM10360
Chapter 10: LPC17xx Ethernet
[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.
12.14 Transmit Status Vector 1 Register (TSV1 - 0x5000 015C)
The Transmit Status Vector 1 register (TSV1) is a Read Only register with an address of
0x5000 015C. The transmit status vector registers store the most recent transmit status
returned by the MAC. Since the status vector consists of more than 4 bytes, status is
distributed over two registers TSV0 and TSV1. These registers are provided for debug
purposes, because the communication between driver software and the Ethernet block
takes place primarily through the frame descriptors. The status register contents are valid
as long as the internal status of the MAC is valid and should typically only be read when
the transmit and receive processes are halted.
lists the bit definitions of the
TSV1 register.
7
Excessive Defer
Packet was deferred in excess of 6071 nibble times in
100 Mbps or 24287 bit times in 10 Mbps mode.
0
8
Excessive Collision
Packet was aborted due to exceeding of maximum allowed
number of collisions.
0
9
Late Collision
Collision occurred beyond collision window, 512 bit times.
0
10
Giant
Byte count in frame was greater than can be represented
in the transmit byte count field in TSV1.
0
11
Underrun
Host side caused buffer underrun.
0
27:12
Total bytes
The total number of bytes transferred including collided
attempts.
0x0
28
Control frame
The frame was a control frame.
0
29
Pause
The frame was a control frame with a valid PAUSE
opcode.
0
30
Backpressure
Carrier-sense method backpressure was previously
applied.
0
31
VLAN
Frame’s length/type field contained 0x8100 which is the
VLAN protocol identifier.
0
Table 138. Transmit Status Vector 0 register (TSV0 - address 0x5000 0158) bit description
Bit
Symbol
Function
Reset
value
Table 139. Transmit Status Vector 1 register (TSV1 - address 0x5000 015C) bit description
Bit
Symbol
Function
Reset
value
15:0
Transmit byte count
The total number of bytes in the frame, not counting the
collided bytes.
0x0
19:16
Transmit collision
count
Number of collisions the current packet incurred during
transmission attempts. The maximum number of collisions
(16) cannot be represented.
0x0
31:20
-
Unused
0x0