
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 23: LAN100 — Ethernet Media Access Controller
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
23-30
For multi-fragment packets, the value of the AlignmentError, RangeError,
LengthError, SymbolError and CRCError bits in all but the last fragment in the packet
will be 0; likewise the value of the FailFilter, Multicast, Broadcast, VLAN and
ControlFrame bits is undened. The status of the last fragment in the packet will copy
the value for these bits from the MII Interface. All fragment statuses will have a valid
LastFrag, EntryLevel, Error, Overrun and NoDescriptor bits.
4.2 Transmit Descriptors and Status
Figure 5 shows the layout of transmit descriptors in memory. The layout and format of
real-time and non-real-time descriptors is identical.
18
ControlFrame
Indicates this is a control frame for ow control, either a pause frame
or a frame with an unsupported opcode.
17:11 -
Unused
10:0
EntryLevel
Size in bytes of the actual data transferred into one fragment buffer.
In other words, this is the size of the packet or fragment as actually
written by the DMA manager for one descriptor. This may be
different from the Control.Size bits 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 EntryLevel value should be 7.
Table 7: Receive Status Information Word
Bit
Name
Function
Figure 5:
Transmit Descriptor Memory Layout
Tx(Rt)Status
0xFEEDB1F8
Packet 0xFEEDB314
Control
0 07
Time-stamp
Pad
Descriptor
0
Tx(Rt)Descriptor
0xFEEDB0EC
0xFEEDB0F8
0xFEEDB118
0xFEEDB0FC
0xFEEDB008
Descriptor
Array
0xFEEDB10C
0xFEEDB11C
0xFEEDB128
0xFEEDB314
Packet 0 header (8 bytes)
0xFEEDB411
0xFEEDB41C
Packet 0 payload (12 bytes)
0xFEEDB32B
0xFEEDB1F8
StatusInfo
StatusTimeStamp
Status
0
0xFEEDB200
0xFEEDB208
0xFEEDB210
Packet 0xFEEDB411
Control
0 07
Time-stamp
Pad
Descriptor
1
Packet 0xFEEDB419
Control
0 07
Time-stamp
Pad
Descriptor
2
Packet 0xFEEDB324
Control
0 07
Time-stamp
Pad
Descriptor
3
Packet 1 header (8 bytes)
0xFEEDB324
Tx(Rt)ConsumeIndex
Tx(Rt)ProduceIndex
Tx(Rt)DescriptorIndex
StatusInfo
StatusTimeStamp
StatusInfo
StatusTimeStamp
StatusInfo
StatusTimeStamp
Status
1
Status
2
Status
3
Status
Array
0xFEEDB31B
Descriptor Array FIFO
Fragment Buffers
Status Array FIFO