AM79C961AVIW AMD (ADVANCED MICRO DEVICES), AM79C961AVIW Datasheet - Page 79

• Manufacturer Part Number: AM79C961AVIW
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM79C961AVIW

• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (max): 5.25V
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 144
• Lead Free Status / Rohs Status: Not Compliant

liding signals changes from active to idle. COL stays
active for 2 bit times at the end of a collision.
Signal Quality Error (SQE) Test
(Heartbeat) Function
The SQE function is disabled when the 10BASE-T port
is selected and in Link Fail state.
Jabber Function
The Jabber function inhibits the twisted pair transmit
function of the T-MAU if the TXD circuit is active for an
excessive period (20 ms–150 ms). This prevents any
one node from disrupting the network due to a
‘stuck-on’ or faulty transmitter. If this maximum transmit
time is exceeded, the T-MAU transmitter circuitry is dis-
abled, the JAB bit is set (CSR4, bit 1), and the COL sig-
nal asserted. Once the transmit data stream to the
T-MAU is removed, an “unjab” time of 250 ms – 750 ms
will elapse before the T-MAU deasserts COL and
re-enables the transmit circuitry.
Power Down
The T-MAU circuitry can be made to go into low power
mode. This feature is useful in battery powered or low
duty cycle systems. The T-MAU will go into power
down mode when RESET is active, coma mode is ac-
tive, or the T-MAU is not selected. Refer to the Power
Down Mode section for a description of the various
power down modes.
internal logic of the T-MAU and places the device into
power down mode. In this mode, the Twisted Pair
driver pins (TXD ,TXP ) are asserted LOW, and the in-
ternal T-MAU status signals (LNKST, RCVPOL, XMT,
RCV and COLLISION) are inactive.
Once the SLEEP pin is deasserted, the T-MAU will be
forced into the Link Fail state. The T-MAU will move to
the Link Pass state only after 5–6 link beat pulses and/
or a single received message is detected on the RXD
pair.
In Snooze mode, the T-MAU receive circuitry will
remain enabled even while the SLEEP pin is driven
LOW.
The T-MAU circuitry will always go into power down
mode if RESET is asserted, coma is enabled, or the
T-MAU is not selected.
Full Duplex Operation
The PCnet-ISA II supports Full Duplex operation on the
10BASE-T, AUI, and GPSI ports. Full Duplex operation
allows simultaneous transmit and receive activity on
the TXD and RXD pairs of the 10BASE-T port, the
DO and DI pairs of the AUI port, and the TXDAT and
RXDAT pins of the GPSI port. It is enabled by the
FDEN and AUIFD bits located in ISACSR9. When op-
Any of the three conditions listed above resets the
Am79C961A
erating in the Full Duplex mode, the following changes
to device operation are made:
Bus Interface/Buffer Management Unit changes:
1. The first 64 bytes of every transmit frame are not
2. Successful reception of the first 64 bytes of every
MAC Engine changes:
1. Changes to the Transmit Deferral mechanism:
2. When the AUI or GPSI port is active, Loss of Carrier
3. The 4.0
4. When the AUI or GPSI port is active, the SQE Test
5. The collision indication input to the MAC Engine is
T-MAU changes:
1. The transmit to receive loopback path in the
2. The collision detect circuit is disabled.
3. The “heartbeat” generation (SQE Test function)
preserved in the transmit FIFO during transmission
of the first 512 bits transmitted on the network, as
described in the Transmit Exception Conditions
section. Instead, when Full Duplex mode is active
and a frame is being transmitted, the XMTFW bits
(CSR80, bits 9, 8) always govern when transmit
DMA is requested.
receive frame is not a requirement for Receive DMA
to begin as described in the Receive Exception
Conditions section. Instead, receive DMA will be
requested as soon as either the RCVFW threshold
(CSR80 bits 12, 13) is reached or a complete valid
receive frame is in the Receive FIFO, regardless of
length. This receive FIFO operation is identical to
when the RPA bit (CSR124, bit 3) is set during Half
Duplex mode operation.
A. Transmission is not deferred while receive is
B. The Inter Packet Gap (IPG) counter which gov-
(LCAR) reporting is disabled (LCAR is still reported
when the 10BASE-T port is active if a packet is
transmitted while in the Link Fail state).
transmission during which the SQE test normally
occurs is disabled.
error (Collision Error, CERR) reporting is disabled
(CERR is still reported when the 10BASE-T port is
active if a packet is transmitted while in the Link Fail
state).
ignored.
T-MAU is disabled.
is disabled.
active.
erns transmit deferral during the IPG between
back-to-back transmits is started when transmit
activity for the first packet ends instead of when
transmit and carrier activity ends.
s carrier sense blinding period after a
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