
116
Agere Systems Inc.
T8302 Internet Protocol Telephone
Advanced RISC Machine (
ARM
)
Data Sheet
July 2001
10 Ethernet 10/100 MAC
(continued)
10.7.18 MAC Controller Transmit Start Register
Table 95. MAC Controller Transmit Start Register
10.7.19 MAC Transmit Status Register
Table 96. MAC Transmit Status Register
Address 0xE001 0804
Bit #
Name
Bit #
15
15
14:0
COUNT
START
Name
START
Description
Start bit. The MAC controller starts attempting to transmit a packet when set. This bit is
reset by the MAC controller when packet transmission is terminated.
Count value.
The 15-bit value is the number of bytes to be transmitted, not including the
CRC
.
14:0
COUNT
Address 0xE001 0808
12
MCOL
4
PAUSEACTIVE
Bit #
Name
Bit #
Name
Bit #
15
15
14
DEF
6
TCNTRL
13
11
10
9
8
EXDEF
7
LATE
Name
EXDEF
SCOL
5
SQEFAIL
CERR
3
TX_VLAN2 TX_VLAN1
Description
COLDET
2
LCRS
1
TXBROAD
ABORTED
0
TXMULT
Excessive deferral (active-high). Indicates transmission ended because of waiting for
more than 24,288 bit times for the medium to become not busy.
Valid on the positive edge of
TX_CLK
. The assertion of this bit is temporary.
Deferral (active-high).
Indicates that a transmission was deferred for one bit time to
24,288 bit times during transmission.
14
DEF
Valid on the positive edge of
TX_CLK
.
Single collision (active-high).
Indicates that there was one collision during transmission of
the previous packet.
13
SCOL
Valid on the positive edge of
TX_CLK
.
Multiple collisions (active-high). Indicates that there was more than one collision during
the transmission of the previous packet.
12
MCOL
Valid on the positive edge of
TX_CLK
.
Collision error (active-high).
Indicates that the previous transmission was stopped
because of excessive collisions as allowed by the
RETRY[1:0]
inputs.
SCOL
and
MCOL
are also valid if
CERR
is active.
11
CERR
Valid on the positive edge of
TX_CLK
.
Collision detected (active-high).
Indicates that a collision has been detected. This signal is
active from the time of a collision until the completion of the 32-bit jam sequence. The
COL
signal is monitored only when the transmitter is actively transmitting data. This signal
is temporary; it may not be held long.
10
COLDET
Valid on the positive edge of
TX_CLK
.