AM79C978A AMD [Advanced Micro Devices], AM79C978A Datasheet - Page 203

• Manufacturer Part Number: AM79C978A
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: AMD [Advanced Micro Devices]

29
28
27
EXDEF
LCOL
LCAR
Late Collision indicates that a col-
Excessive Deferral. Indicates that
the transmitter has experienced
Excessive Deferral on this trans-
mit frame, where Excessive De-
ferral is defined in the ISO 8802-3
(IEEE/ANSI 802.3) standard. Ex-
cessive Deferral will also set the
interrupt bit EXDINT (CSR5,
bit 7).
lision has occurred after the first
channel slot time has elapsed.
The
networkingAm79C978A control-
ler does not retry on late colli-
sions. LCOL is set by the
Am79C978A
cleared by the host.
Loss of Carrier is set when the
carrier
Am79C978A controller initiat-
ed transmission when operat-
ing in half-duplex mode. The
Am79C978A controller does
not retry upon loss of carrier. It
will continue to transmit the
whole frame until done. LCAR
will not be set when the device
is
mode. LCAR is not valid in In-
ternal Loopback Mode. LCAR
is set by the Am79C978A con-
troller and cleared by the host.
operating
Am79C978A
is
lost
controller
in
during
full-duplex
home
Am79C978A
and
an
26
25-4
3-0
TMD3
Bit
31-0
RTRY
RES
TRC
US
Name
Retry error indicates that the
LCAR will be set when the PHY
is in Link Fail state during
transmission.
transmitter has failed after 16 at-
tempts to successfully transmit a
message, due to repeated colli-
sions on the medium. If DRTY is
set to 1 in the MODE register,
RTRY will set after one failed
transmission attempt. RTRY is
set by the Am79C978A controller
and cleared by the host.
Reserved locations.
Transmit Retry Count. Indicates
the number of transmit retries of
the associated packet. The maxi-
mum count is 15. However, if a
RETRY error occurs, the count
will roll over to 0.
In this case only, the Transmit
Retry Count value of 0 should be
interpreted as meaning 16. TRC
is written by the Am79C978A
controller into the last transmit
descriptor of a frame, or when an
error terminates a frame. Valid
only when OWN is cleared to 0.
User Space. Reserved for user
defined space.
Description
203