
112
Agere Systems Inc.
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
Data Sheet
July 2001
10 Ethernet 10/100 MAC
(continued)
10.7.12 MAC Receive FIFO Register
Table 89. MAC Receive FIFO Register
10.7.13 MAC Receive Control FIFO Register
This register is used to access the status words in the receive control FIFO. Each status word has the format
shown in Table 90.
Table 90. MAC Receive Control FIFO Register
Address 0xE001 003C
Bit #
Name
Bit #
31:0
31:0
DATA
Name
DATA
Description
Data (read-only). Data received into this register, LSB first.
Address 0xE001 0040
29
FAE
23
MULT
17
RX_VLAN1
Bit #
Name
Bit #
Name
Bit #
Name
Bit #
31
31
IFG
25
LONG
19
RPAUSE
Name
IFG
30
28
CRC
22
BROAD
16
RXEROUT
Description
27
26
RXJAB
24
PHYS
18
RX_VLAN2
RUNT
21
RCNTRL
15:0
RXCOUNT
FRAG
20
RUNSUP
—
—
Short IFG (active-high).
Indicates that the interframe gap prior to the start of the packet was
less than 76 bit times.
Valid on the positive edge of
RX_CLK
.
Receive jabber error (active-high). Indicates that the receive packet length was greater than
1518 bytes, and that the packet had a bad
CRC
or
FAE
.
30
RXJAB
Valid on the positive edge of
RX_CLK
.
Frame alignment error (active-high).
Indicates a packet was received with a frame alignment
error. An
FAE
occurs when the resultant remainder from the division between the number of
bits in a frame and eight is nonzero (nonintegral number of octets), the
CRC
is invalid, and
the octet counters are greater than or equal to 64 and less than or equal to 1518. Valid on
the positive edge of
RX_CLK
.
Dribble bits have no effect.
CRC error (active-high).
Indicates a packet was received with a bit count having a mod 8
remainder equal to 0 (integral number of octets), and that the packet had an incorrect
CRC
.
29
FAE
28
CRC
Valid on the positive edge of
RX_CLK
.
Runt packet (active-high).
Indicates a packet was received with a byte count
(including
CRC
) <64, and the packet had a good
CRC
.
27
RUNT
Valid on the positive edge of
RX_CLK
.
Fragment (active-high).
Indicates a packet was received with a byte count
(including
CRC
) <64, and the packet had a bad
CRC
or
FAE
.
26
FRAG
Valid on the positive edge of
RX_CLK
.