User Manual
BCM1250/BCM1125/BCM1125H
10/21/02
B r o a d c o m C o r p o r a t i o n
Document
1250_1125-UM100CB-R
Section 9: Ethernet MACs Page
297
8-B
IT
EOP F
LAGGED
P
ACKET
FIFO
EOP flagged Packet FIFO mode uses one control line as a data valid signal and the other to flag end of packet.
The start of packet is one cycle after an end of packet, or the first data after the valid signal has risen. Any
SOPs that occur between an SOP and EOP are ignored, so in
there is not an SOP flagged in the
cycle marked X, one cycle after TXEN/RXDV was low. This mode is good for streaming data that uses only
the data valid signal. If the EOP flag is always low the interface will transfer a single never-ending packet for
as long as DMA buffers are provided.
Figure 63: 8-Bit Packet FIFO EOP Style
TXEN/RXDV
TXER/RXER
TXD/RXD[7:0]
TCLKO/RCLK
55
SOP
EOP SOP
X
Table 173: Codes for 8-Bit EOP Bypass Mode
TXEN / RXDV
TXER / RXER
Valid Data, Start of Packet
0->1 at start of cycle
anything
1
1 previous cycle
Valid Data
1
0
Valid Data, End of Packet
1
1
Data Not Valid
0
anything
Содержание BCM1125
Страница 18: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xviii Document 1250_1125 UM100CB R ...
Страница 28: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xxviii Document 1250_1125 UM100CB R ...
Страница 515: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page vii Index Document 1250_1125 UM100CB R ...