AM79C970A Advanced Micro Devices, AM79C970A Datasheet - Page 168

• Manufacturer Part Number: AM79C970A
• Description: PCnet-PCI II Single-Chip Full-Duplex Ethernet Controller for PCI Local Bus Product
• Manufacturer: Advanced Micro Devices

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AMD
EXDEF
RTRY
LCOL
LCAR
start of a new frame and starts a
new transmission.
UFLO is set by the PCnet-PCI II
controller
the host.
Excessive Deferral. Indicates
that the transmitter has experi-
enced Excessive Deferral on this
transmit frame, where Excessive
Deferral is defined in ISO 8802-3
(IEEE/ANSI 802.3). Excessive
Deferral will also set the interrupt
bit EXDINT (CSR5, bit 7).
Late Collision indicates that a
collision has occurred after the
first slot time of the channel has
elapsed. The PCnet-PCI II con-
troller does not retry on late
collisions.
the PCnet-PCI II controller and
cleared by the host.
Loss of Carrier is set when
the
a PCnet-PCI II controller-initiated
transmission when in AUI or
GPSI mode and the device is op-
erating in half-duplex mode. The
PCnet-PCI II 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 operat-
ing in full-duplex mode and the
AUI or GPSI port is active. LCAR
is not valid in Internal Loopback
Mode.
the PCnet-PCI II controller and
cleared by the host.
In 10BASE-T mode, LCAR will
be set when the T-MAU was
in
the transmission.
Retry error indicates that the
transmitter has failed after 16 at-
tempts to successfully transmit a
message, due to repeated colli-
Link
carrier
LCAR
Fail
LCOL
and
is
state
is
cleared
lost
is
set
P R E L I M I N A R Y
set
during
during
Am79C970A
by
by
by
25–16 TDR
15–4
3–0
TMD3
Bit
31–0
Name
RES
TRC
RES
sions on the medium. If DRTY is
set to ONE in the MODE register,
RTRY will set after 1 failed trans-
mission attempt. RTRY is set by
the PCnet-PCI II controller and
cleared by the host.
Time Domain Reflectometer re-
flects the state of an internal
PCnet-PCI II controller counter
that counts at a 10 MHz rate from
the start of a transmission to the
occurrence of a collision or loss
of carrier. This value is useful in
determining
distance to a cable fault. The
TDR value is written by the
PCnet-PCI II controller and is
valid only if RTRY is set.
Note that 10 MHz gives very low
resolution and in general has
not been found to be particularly
useful. This feature is here
primarily
compatibility with the C-LANCE
device (Am79C90).
Reserved locations.
Transmit Retry Count. Indicates
the number of transmit retries
of the associated packet. The
maximum count is 15. However,
if a RETRY error occurs, the
count will roll over to ZERO. In
this case only, the Transmit Retry
Count value of ZERO should be
interpreted as meaning 16. TRC
is written by the PCnet-PCI II
controller into the last transmit
descriptor of a frame, or when
an error terminates a frame.
Valid only when OWN is cleared
to ZERO.
Description
Reserved locations.
to
the
maintain
approximate
full