
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
23-32
The Packet word is a 32-bit byte-aligned address value containing the base address
of the data buffer. The time-stamp eld is a 32-bit value which is compared against
the internal Time-stamp Counter for real-time transmission. The denition of the
Table 10 lists the elds in the Transmit Status Structure.
The Transmit Status Structure consists of two words. The StatusTimeStamp word
contains a copy of the Time-stamp Counter value at the time the Transmit Status
Structure was received from the MII Interface. If the fragment is not the last fragment
in the packet, the time-stamp value will be a copy of the Time-stamp Counter at the
time all data in the fragment was accepted by the Tx retry module. The StatusInfo
Table 9: Transmit Descriptor Control Word
Bit
Name
Function
31
Interrupt If set, generate an Tx(Rt)Done interrupt when the data in this packet or
packet fragment has been sent and the associated status information has
been committed to memory.
30
Last
If set, this bit indicates that this is the descriptor for the last fragment in the
receive packet. If not set, the fragment from the next descriptor should be
appended.
29
CRC
If set, append a hardware CRC to the packet.
28
Pad
If set, pad short packets to 64 bytes.
27
Huge
If set, this bit enables huge frames. When not set, this bit prevents
transmission of more than MAXF[15:0]. When set, it allows unlimited frame
sizes.
26
Override Per-packet override. If set, bits [30:27] override the defaults from the MII
Interface internal registers. If not set, Control bits [30:27] will be ignored
and the default values from the MII Interface will be used.
25:11
Unused
10:0
Size
Size in bytes of the data buffer. This is the size of the packet or fragment as
it must be fetched by the DMA manager. In most cases, it will be equal to
the byte size of the data buffer pointed to by the Packet eld of the
descriptor. Size is –1 encoded, e.g., a buffer of 8 bytes is encoded as the
Size value 7.
Table 10: Transmit Status Structure
Name
Address
Offset
Siz
e
Function
StatusInfo
0x0
31:0 Transmit status return ags, see
Table 11.
StatusTimeStamp 0x4
31:0 Time-stamp of transmit completion.