DM9000
ISA to Ethernet MAC Controller with Integrated 10/100 PHY
Final
15
Version: DM9000-DS-F02
June 26, 2002
6.7 RX Status Register ( 06H )
Bit
Name
Default
Description
7
RF
0,RO
Runt Frame
It is set to indicate that the size of the received frame is smaller than 64 bytes
6
MF
0,RO
Multicast Frame
It is set to indicate that the received frame has a multicast address
5
LCS
0,RO
Late Collision Seen
It is set to indicate that a late collision is found during the frame reception
4
RWTO
0,RO
Receive Watchdog Time-Out
It is set to indicate that it receives more than 2048 bytes
3
PLE
0,RO
Physical Layer Error
It is set to indicate that a physical layer error is found during the frame reception
2
AE
0,RO
Alignment Error
It is set to indicate that the received frame ends with a non-byte boundary
1
CE
0,RO
CRC Error
It is set to indicate that the received frame ends with a CRC error
0
FOE
0,RO
FIFO Overflow Error
It is set to indicate that a FIFO overflow error happens during the frame reception
6.8 Receive Overflow Counter Register ( 07H )
Bit
Name
Default
Description
7
RXFU
0,R/C
Receive Overflow Counter Overflow
This bit is set when the ROC has an overflow condition
6:0
ROC
0,R/C
Receive Overflow Counter
This is a statistic counter to indicate the received packet count upon FIFO overflow
6.9 Back Pressure Threshold Register (08H)
Bit
Name
Default
Description
7:4
BPHW
3H, RW
Back Pressure High Water Overflow Threshold. MAC will generate the jam pattern
when RX SRAM free space is lower than this threshold value
Default is 3K-byte free space. Please do not exceed SRAM size
(1 unit=1K bytes)
3:0
JPT
7H, RW
Jam Pattern Time. Default is 200us
bit3 bit2 bit1 bit0 time
0 0 0 0 5us
0 0 0 1 10us
0 0 1 0 15us
0 0 1 1 25us
0 1 0 0 50us
0 1 0 1 100us
0 1 1 0 150us
0 1 1 1 200us
1 0 0 0 250us
1 0 0 1 300us
1 0 1 0 350us
1 0 1 1 400us
1 1 0 0 450us
1 1 0 1 500us
1 1 1 0 550us
1 1 1 1 600us