Network Router User Manual

47
STP2002QFP
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
Sun Microsystems,
less specified otherwise.
Figure 13. RxFIFO Organization
junk
junk
junk
junk
Frame #1 Data
Frame #1 Data
Frame #1 Control
32-Bit
Mode
Wrap-
Around
FIFO
64-Bit
Mode
031
32
Tag_1
63
Tag_0
Addr_0
junk
0
.
.
.
.
0
0
1
0
.
.
.
.
0
0
1
Read_Ptr
Frame #2 Data
Frame #2 Data
Frame #2 Control
0
.
.
.
.
0
0
1
0
.
.
.
.
0
1
junk
Frame #3 Data
.
.
.
.
Frame #3 Data
.
.
.
.
0
.
.
.
.
.
.
0
.
.
.
.
.
Shadow
Write_Ptr
Frame #n Data
Frame #n Data
0
.
.
.
0
0
1
1
Frame #n Control
Frame #n Control
junk
junk
Write_Ptr
x
x
x
x
x
x
x
x
Addr 255
Tag_0/Tag_1
1
Frame Size
Frame Checksum
15 0
Frame Status
Word
16
Rsrvd
Rx_
Abort
3031
29