CS8900A datasheet(64/128 Pages) CIRRUS

64 / 128 page

DS271PP3

CS8900A

Crystal LAN™ ISA Ethernet Controller

CIRRUS LOGIC PRODUCT DATA SHEET

4.4.17 Register 14: Line Status

(LineST, Read-only, Address: PacketPage base + 0134h)

LineST reports the status of the Ethernet physical interface.

010100

These bits provide an internal address used by the CS8900A to identify this as the Line Status

Bit 0.

LinkOK

If set, the 10BASE-T link has not failed. When clear, the link has failed, either because the

CS8900A has just come out of reset, or because the receiver has not detected any activity (link

pulses or received packets) for at least 50 ms.

AUI

If set, the CS8900A is using the AUI.

10BT

If set, the CS8900A is using the 10BASE-T interface.

PolarityOK

If set, the polarity of the 10BASE-T receive signal (at the RXD+ / RXD- inputs) is correct. If clear,

the polarity is reversed. If PolarityDis (Register 13, LineCTL, Bit C) is clear, the polarity is auto-

matically corrected, if needed. The PolarityOK status bit shows the true state of the incoming

polarity independent of the PolarityDis control bit. Thus, if PolarityDis is clear and PolarityOK is

clear, then the receive polarity is inverted, and corrected.

CRS

This bit tells the host the status of an incoming frame. If CRS is set, a frame is currently being

received. CRS remains asserted until the end of frame (EOF). At EOF, CRS goes inactive in

about 1.3 to 2.3 bit times after the last low-to-high transition of the recovered data.

Reset value is:

0000 0000 0001 0100

765

4321

LinkOK

010100

DCBA

CRS

PolarityOK

10BT

AUI

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