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Programmable Digital Input Multiplexer

IP.com Disclosure Number: IPCOM000042197D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kendrick, VC: AUTHOR

Abstract

This article concerns a versatile microprocessor-controlled multiplexing system, implementable in state-of-the-art VLSI semiconductor technology, for digital data gathering applications. This system and technology allows 16 analog channels, an 8-bit analog-to-digital (A/D) converter, and the microprocessor controller to be implemented on a single module. Referring to the illustration, the system accepts voltage inputs in the range +16.5 to -60.0 volts, at its inputs 1, translates them through dividers and level shifters 2 into corresponding signal samples in the narrower voltage range 0.0 to +5.0 volts, multiplexes the outputs of block 2 in analog multiplexer 3, translates outputs of the latter block into corresponding 8-bit digital functions in A/D converter block 4, and stores the digital byte results in memory 5.

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Programmable Digital Input Multiplexer

This article concerns a versatile microprocessor-controlled multiplexing system, implementable in state-of-the-art VLSI semiconductor technology, for digital data gathering applications. This system and technology allows 16 analog channels, an 8-bit analog-to-digital (A/D) converter, and the microprocessor controller to be implemented on a single module. Referring to the illustration, the system accepts voltage inputs in the range +16.5 to -60.0 volts, at its inputs 1, translates them through dividers and level shifters 2 into corresponding signal samples in the narrower voltage range 0.0 to +5.0 volts, multiplexes the outputs of block 2 in analog multiplexer 3, translates outputs of the latter block into corresponding 8- bit digital functions in A/D converter block 4, and stores the digital byte results in memory 5. The operations are controlled and coordinated by microprocessor 6. This gives the following results for the indicated analog voltage inputs:

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The 8-bit functions entered into memory 5 are compared by the microprocessor with values previously stored for respective points (input ports), allowing for acceptance of inputs within the prescribed range and rejection of inputs outside that range. The memory capacity is sufficient to allow for storage of multiple samples for later comparison (e.g., if the acceptance range is currently undefined).

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