ICS1893BF Data Sheet - Release
Chapter 6 Functional Blocks
6.5.7 10Base-T Operation: Carrier Detection
The ICS1893BF has a 10Base-T Carrier Detection Function that establishes the state of its Carrier Sense
signal (CRS), based upon the state of its Transmit and Receive state machines. These functions indicate
whether the ICS1893BF is (1) transmitting data, (2) receiving data, or (3) in a collision state (that is, the
ICS1893BF is both transmitting and receiving data on its twisted-pair medium, as defined in the ISO/IEC
8802-3 standard). When the ICS1893BF is configured for:
• Half-duplex operations, the ICS1893BF asserts its CRS signal when either transmitting or receiving data.
• Full-duplex operations, the ICS1893BF asserts its CRS signal only when it is receiving data.
6.5.8 10Base-T Operation: Collision Detection
The ICS1893BF has a 10Base-T Collision Detection Function that establishes the state of its Collision
Detection signal (COL) based upon both (1) the state of its Receiver state machine and (2) the state of its
Transmit state machine. When the ICS1893BF is operating in:
• Half-duplex mode, the ICS1893BF asserts its COL signal to indicate it is receiving data while
transmission of data is also in progress.
• Full-duplex mode, the ICS1893BF always sets its COL signal to FALSE.
6.5.9 10Base-T Operation: Jabber
The ICS1893BF has an ISO/IEC compliant Jabber Detection Function that, when enabled, monitors the
data stream sent to its Twisted-Pair Transmitter to ensure that it does not exceed the 10Base-T Jabber
activation time limit (that is, the maximum transmission time). For more information, see Section 9.5.18,
“10Base-T: Jabber Timing”.
When the Jabber Detection Function detects that its transmission time exceeds the maximum Jabber
activation time limit and Jabber Detection is enabled, the ICS1893BF asserts its Collision Detect (COL)
signal. During this ISO/IEC specified ‘jabber de-activation time’, the ICS1893BF transmit data stream is
interrupted and prevented from reaching its Twisted-Pair Transmitter. During this time, when interrupting
the data stream and asserting its COL signal, the ICS1893BF transmits Normal Link Pulses and sets its
QuickPoll Detailed Status Register’s Jabber Detected bit (bit 17.2) to logic one. This bit is a latching high
(LH) bit. (For more information on latching high and latching low bits, see Section 7.1.4.1, “Latching High
Bits” and Section 7.1.4.2, “Latching Low Bits”.)
The ICS1893BF provides an STA with the ability to disable the Jabber Detection Function using the Jabber
Inhibit bit (bit 18.5 in the 10Base-T Operations Register). Setting bit 18.5 to logic:
• Zero (the default) enables the Jabber Detection Function.
• One disables the Jabber Detection Function.
6.5.10 10Base-T Operation: SQE Test
The ICS1893BF has an ISO/IEC compliant Signal Quality Error (SQE) Test Function used exclusively for
10Base-T operations. When enabled, the ICS1893BF performs the SQE Test at the completion of each
transmitted packet (that is, whenever its TX_EN signal transitions from asserted to de-asserted). When the
ICS1893BF executes its SQE Test, it asserts the COL signal to its MAC Interface for a pre-determined time
duration (ISO/IEC specified). [For more information, see Section 9.5.17, “10Base-T: Heartbeat Timing
(SQE)”.]
ICS1893BF, Rev. E, 8/11/09
August, 2009
Copyright © 2009, IDT, Inc.
All rights reserved.
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