am79c989 Advanced Micro Devices, am79c989 Datasheet - Page 26

• Manufacturer Part Number: am79c989
• Description: Quad Ethernet Switching Transceiver
• Manufacturer: Advanced Micro Devices

Control Register (Reg 18)
The Control Register (Reg 18) configures the port in
conjunction with the Auto-Negotiation registers. The
26
Bit(s)
14:6
15
5
4
3
2
1
0
Extended Distance
Polarity Correction
Force Link Good
Interrupt Enable
Auto Receive
SQE_TEST
Generation
Link Pulse
AUI Select
Reserved
Disable
Disable
Disable
Enable
Enable
Enable
Name
1 = 10BASE-T link integrity state machine is forced to the “link
good” state;
0 = Normal operation resumes.
For internal test only (when link pulses are absent).
Not for general use in 10BASE-T applications.
Written and read as zero.
1 = For port 0, the Interrupt function through the QINT/CI- pin will
be active and the AUI port, if selected (bit 2 set), will operate in PCI
mode.
0 = For port 0, the interrupt function will not be available.
Ports 1, 2, and 3 are don’t cares.
Not effected by SRESET.
1 = Link pulses sent from the 10BASE-T transmitter are
suppressed;
0 = Link Pulses not suppressed.
1 = Polarity correction circuit at the front-end of the receive port
disabled (when the receive function is disabled, the receive port will
only accept frames with correct polarity);
interface of the device.
1 = For port 0, Attachment Unit Interface is substituted for
10BASE-T port 0;
Ports 1, 2, and 3 are don’t cares. Not effected by SRESET.
1 = 10BASE-T receive squelch thresholds reduced for reception of
frames farther than 100 meters.
0 = Squelch thresholds at standard 100 meter distance.
1 = SQE heartbeat, which occurs after each transmission, disabled;
0 = Heartbeat asserted on QCLSN approximately 1 s after
transmission, for a duration of 1 s;
When the port is configured for full duplex, heartbeat signal is
automatically disabled.
0 = Self-correcting polarity circuit will be enabled at the receive
0 = Port 0 reverts to 10BASE-T function.
Table 18. Control Register (Reg 18)
P R E L I M I N A R Y
Am79C989
Description
Control Register contains Read/Write (R/W) or Read/
Only (R/O) bits. This register is duplicated for each
port.
Read/
Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/O
Default/
Reset
0
1
0
0
0
0
0
0