AX88140AP ETC, AX88140AP Datasheet - Page 32

• Manufacturer Part Number: AX88140AP
• Description: Fast Ethernet MAC Controller
• Manufacturer: ETC

5.2.2 Receive Descriptor 1 (RDES1)
5.2.3 Receive Descriptor 2 (RDES2)
5.2.4 Receive Descriptor 3 (RDES3)
FIELD
FIELD
FIELD
31:11
10:0
31:0
31:0
10
9
8
7
6
5
4
3
2
1
0
AX88140A
Reserved.--Written as “0” for future compatibility concern.
RBS - Receive Data Buffer Size
Indicates the size in bytes of the data buffer. If this field is 0, the AX88140A ignores this buffer.
The buffer size must be a multiple of 4.
Data Buffer Pointer
Indicates the physical address of data buffer. The buffer must be long-word-aligned (RDES2<1:0>=00).
Address Pointer
Indicates the physical address of next descriptor. The address must be long-word aligned (RDES3<1:0>=00).
MF - Multicast Frame Indicates that this frame is a multicast address.
This field is valid only when last descriptor (RDES0<8>) is set.
FS - First Descriptor
LS - Last Descriptor
TL - Frame Too Long. Frame length grater then 1518 bytes. Active high.
This field is valid only when last descriptor (RDES0<8>) is set.
CS - Collision Seen. This is a late collision.
This field is valid only when last descriptor (RDES0<8>) is set.
Reserved.--Written as “0” for future compatibility concern.
RW - Receive Watchdog time expire. Active high.
This field is valid only when last descriptor (RDES0<8>) is set.
RE - Report on MII Error. Active high.
DB - Dribbling Bit Active high.
If set, and CRC error (RDES0<1>) is reset, then the packet is valid.
CE - CRC Error. Active high.
This field is valid only when last descriptor (RDES0<8>) is set.
FIFO Overrun. Active high.
Tab - 32 Receive Descriptor 0
Tab - 33 Receive Descriptor 1
Tab - 34 Receive Descriptor 2
Tab - 35 Receive Descriptor 3
DESCRIPTION
DESCRIPTION
DESCRIPTION
1
0
1
0
32
Indicates that this descriptor contains the first buffer of a
frame.
Indicates that this descriptor is the middle or last buffer of
a frame.
Indicates that the buffers pointed to by this descriptor, are
the last buffers
Indicates that this descriptor is the middle or first buffer of
a frame.
ASIX ELECTRONICS CORPORATION
PRELIMINARY