AM79C940JC/W AMD [Advanced Micro Devices], AM79C940JC/W Datasheet - Page 21

• Manufacturer Part Number: AM79C940JC/W
• Manufacturer: AMD [Advanced Micro Devices]

Notes:
1. PORTSEL [1–0] and ENPLSIO are located in the PLS Configuration Control register (REG ADDR 14).
2. This pin should be externally terminated, if unused, to reduce power consumption.
Notes:
1. PORTSEL [1–0] and ENPLSIO are located in the PLS Configuration Control register (REG ADDR 14).
2. This pin should be externally terminated, if unused, to reduce power consumption.
DXCVR
Disable Transceiver (Output)
An output from the MACE device to indicate the net-
work port in use, as programmed by the ASEL bit or the
PORTSEL [1–0] bits. The output is provided to allow
power down of an external DC-to-DC converter, typi-
cally used to provide the voltage requirements for an
external 10BASE2 transceiver.
When the Auto Select (ASEL) feature is enabled, the
state of the PORTSEL [1–0] bits is overridden, and the
network interface will be selected by the MACE device,
SLEEP
SLEEP
0
1
1
1
1
1
0
1
1
1
1
1
PORTSEL
[1–0]
XX
XX
00
01
10
11
PORTSEL
[1-0]
XX
XX
00
01
10
11
ENPLSIO
X
1
1
1
1
0
ENDPLSIO
X
1
1
1
1
0
RXCRS Configuration
RXDAT Configuration
Sleep Mode
AUI
10BASE-T
DAI Port
GPSI
Status Disabled
Interface Description
Am79C940
Sleep Mode
AUI
10BASE-T
DAI Port
GPSI
Status Disabled
Interface Description
dependent only on the status of the 10BASE-T link. If
the link is active (LNKST pin driven LOW) the
10BASE-T port will be used as the active network inter-
face. If the link is inactive (LNKST pin pulled HIGH) the
AUI port will be used as the active network interface.
Auto Select will continue to operate even when the
SLEEP pin is asserted if the RWAKE bit has been set.
The AWAKE bit does not allow the Auto Select func-
tion, and only the receive section of 10BASE-T port will
be active (DXCVR = HIGH).
Active (HIGH) when either the 10BASE-T or DAI port
is selected. Inactive (LOW) when the AUI or GPSI port
is selected.
High Impedance
High Impedance (Note 2)
High Impedance (Note 2)
RXDAT Input
RXDAT Input
High Impedance (Note 2)
High Impedance
RXCRS Output
RXCRS Output
RXCRS Output
RXCRS Output
High Impedance (Note 2)
Pin Function
Pin Function
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