1893AFLF IDT, 1893AFLF Datasheet - Page 43

• Manufacturer Part Number: 1893AFLF
• Description: Ethernet ICs 3.3V 10/100 BASE TX INTEGRATED PHYCEIVER
• Manufacturer: IDT
• Type: Integrated PHY Transceiverr

Specifications of 1893AFLF

• Rohs: yes
• Product: Ethernet Transceivers
• Data Rate: 10 Mb/s, 100 Mb/s
• Supply Voltage - Max: 3.47 V
• Supply Voltage - Min: 3.14 V
• Maximum Operating Temperature: + 70 C
• Package / Case: SSOP-48
• Ethernet Connection Type: 100Base-TX, 10Base-T
• Maximum Supply Current: 160 mA
• Minimum Operating Temperature: 0 C
• Standard Supported: 802.3
• Part # Aliases: ICS1893AFLF

7.3.5 PCS Control Signal Generation
7.3.6 4B/5B Encoding/Decoding
ICS1893AF, Rev. D 10/26/04
For the PCS sublayer, there are two control signals: a Carrier Sense signal (CRS) and a Collision Detect
signal (COL).
The CRS control signals is generated as follows:
1. When a logic zero is detected in an idle bit stream, the Receive Functions examines the ensuing bits.
2. When the Receive Functions find the first two non-contiguous zero bits, the Receive state machine
3. As a result, the Boolean Receiving variable is set to TRUE.
4. Consequently, the Carrier Sense state machine moves into the Carrier Sense ‘on’ state, which asserts
5. If the PCS Functions:
The COL control signal is generated by the transmit modules. For details, see
Transmit
The 4B/5B encoding methodology maps each 4-bit nibble to a 5-bit symbol (also called a “code group”).
There are 32 five-bit symbols, which include the following:
•
•
Note:
Of the 32 five-bit symbols, 16 five-bit symbols are required to represent the 4-bit nibbles.
The remaining 16 five-bit symbols are available for control functions. The IEEE Standard defines 6
symbols for control, and the remaining 10 symbols of this grouping are invalid. The 6 control symbols
include the following:
If the ICS1893AF PCS receives:
– /H/, which represents a Halt, also used to signify a Transmit Error
– /I/, which represents an IDLE
– /J/, which represents the first symbol of the Start-of-Stream Delimiter (SSD)
– /K/, which represents the second symbol of the Start-of-Stream Delimiter (SSD)
– /T/, which represents the first symbol of the End-of-Stream Delimiter (ESD)
– /R/, which represents the second symbol of the End-of-Stream Delimiter (ESD)
– One of the 10 undefined symbols, it sets its QuickPoll Detailed Status Register’s Invalid Symbol bit
– A Halt symbol, it sets the Halt Symbol Detected bit in its QuickPoll Detailed Status Register (bit 17.6)
ICS1893AF Data Sheet - Release
moves into the Carrier Detect state.
the CRS signal.
a. Cannot confirm either the /I/J/ (IDLE, J) symbols or the /J/K/ symbols, the receive error signal
b. Can confirm the /I/J/K/ symbols, then the Receive state machine transitions to the ‘Receive’ state.
(bit 17.7) to logic one.
to logic one.
(RX_ER) is asserted, and the Receive state machine returns to the IDLE state. In IDLE, the
Boolean Receiving variable is set to FALSE, thereby causing the Carrier Sense state machine to
set the CRS signal to FALSE.
An STA can force the ICS1893AF to transmit symbols that are typically classified as invalid, by
both (1) setting the Extended Control Register’s Transmit Invalid Codes bit (bit 16.2) to logic one
and (2) asserting the associated TXER signal. For more information, see
Error Code Test (bit
Module”.
16.2)”.
Copyright © 2004, Integrated Circuit Systems, Inc.
All rights reserved.
43
Section 7.3.3.1, “PCS
Chapter 7 Functional Blocks
Section 8.11.7, “Invalid
October, 2004