Browse Prior Art Database

Single Chip Adapter

IP.com Disclosure Number: IPCOM000039294D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 75K

Publishing Venue

IBM

Related People

Blue, LA: AUTHOR [+4]

Abstract

This article describes a single-chip implementation of the transmission line analog interface for the IEEE 802.5 Token Ring Local Area Network. The functional implementation of this interface on a single chip is made possible by using three on-chip noise-isolation techniques. First, the analog and digital grounds were separated and brought out to different pins on the module. Second, cascode current switch logic was used to minimize noise on the voltage and ground buses. Third, highly sensitive circuits were physically isolated from the high power and digital circuits. The combination of these design "techniques" enabled the circuitry to be contained on a single chip. A block diagram of the chip is shown in the figure.

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Single Chip Adapter

This article describes a single-chip implementation of the transmission line analog interface for the IEEE 802.5 Token Ring Local Area Network. The functional implementation of this interface on a single chip is made possible by using three on-chip noise-isolation techniques. First, the analog and digital grounds were separated and brought out to different pins on the module. Second, cascode current switch logic was used to minimize noise on the voltage and ground buses. Third, highly sensitive circuits were physically isolated from the high power and digital circuits. The combination of these design "techniques" enabled the circuitry to be contained on a single chip. A block diagram of the chip is shown in the figure. The chip performs the following functions: Receives Manchester signal from an upstream

station. Equalizes the signal.

Reclocks the signal using a phase-locked loop (PLL).

Derives the clock using a frequency detector.

Transmits the data at the derived clock rate.

Detects phase and frequency lock of VCO

(voltage-controlled oscillator) and signal.

Detects energy on the receive line.

Determines if a wire fault exists on the line.

Indicates Ready whenever data is being received

and the PLL is locked to it.

Performs a diagnostic wrap test to check the loop

prior to connection to the ring. In addition to the above functions, the chip has numerous features which increase its flexibility and adaptability to other applications. The chip h...