ICS1893 datasheet(55/152 Pages) ICST

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Chapter 7

Functional Blocks

ICS1893 Rev C 6/6/00

June, 2000

ICS1893 - Release

7.5.11

10Base-T Operation: Twisted-Pair Transmitter

The 10Base-T Twisted-Pair Transmitter is functionally similar to the 100Base-TX Twisted-Pair Transmitter.

The primary differences are in the data rate and signaling, as specified in the ISO/IEC specifications. For

more information, see Section 7.4.5, “100Base-TX Operation: Twisted-Pair Transmitter”.

7.5.12

10Base-T Operation: Twisted-Pair Receiver

The 10Base-T Twisted-Pair Receiver is functionally similar the 100Base-TX Twisted-Pair Receiver. The

primary differences are in the data rate and signaling, as specified in the ISO/IEC specifications. For more

information, see Section 7.4.6, “100Base-TX Operation: Twisted-Pair Receiver”.

7.5.13

10Base-T Operation: Auto Polarity Correction

The ICS1893 can sense and then automatically correct a signal polarity that is reversed on its Twisted-Pair

Receiver inputs. A signal polarity reversal occurs when the input signals on an ICS1893’s TP_RXP and

TP_RXN pins are crossed or swapped (a problem that can occur during network installation or wiring).

The ICS1893 accomplishes reversed signal polarity detection and correction by examining the signal

polarity of the Normal Link Pulses (NLPs). In 10Base-T mode, an ICS1893 transmits and receives NLPs

when its link is in the Idle state. In 100Base-TX mode, an ICS1893 transmits and receives NLPs during

Auto-Negotiation. An STA can control this feature using the 10Base-T Operations Register bit 18.3, the

Auto Polarity-Inhibit bit. When this bit is logic:

• Zero, the ICS1893 automatically senses and corrects a reversed or inverted signal polarity on its

Twisted-Pair Receive pins (TP_RXP and TP_RXN).

• One, the ICS1893 disables this feature.

When an ICS1893 detects a reversed signal polarity on its Twisted-Pair Receiver pins and the Auto

Polarity-Inhibit bit is also logic zero (enabled), the ICS1893 (1) automatically corrects the data stream and

(2) sets its Polarity Reversed bit (bit 18.14) to logic one, to indicate to the STA that this situation exists. Bit

18.14 is a latching high (LH) bit. (For more information on latching high and latching low bits, see Section

8.1.4.1, “Latching High Bits”and Section 8.1.4.2, “Latching Low Bits”.)

Note:

The Auto Polarity Correction Function is primarily a 10Base-T operation. However, it is part of the

Twisted-Pair Receiver and is operational during the 100Base-TX auto-negotiation process.

7.5.14

10Base-T Operation: Isolation Transformer

The 10Base-T Isolation Transformer operates the same as the 100Base-TX Isolation Transformer. In fact,

in a typical ICS1893 application they are the same unit. For more information, see Section 7.4.8,

“100Base-TX Operation: Isolation Transformer”.

ICS1893 датащи(PDF) 55 Page - Integrated Circuit Systems