Browse Prior Art Database

Mode Select Technique to Save I/O Pins

IP.com Disclosure Number: IPCOM000077360D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Dumstorff, EF: AUTHOR

Abstract

Module 5 is designed to function in two modes 1 and 2 which must be selected internal to the module. Logic generating lines A, B and C are associated with mode 1 while logic generating lines D, E and F are associated with mode 2. An unused combination of the input signals generated on lines A, B and C is decoded at 6 when it is desired to select mode 2. Decoding the lines A, B and C to select mode 2 effects mode selection without the use of an additional input line or pin connection. This technique can be applied to discriminate between many operating modes, so long as the driving signals have an unused state and are separable such as to allow decoding internally on the module.

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Mode Select Technique to Save I/O Pins

Module 5 is designed to function in two modes 1 and 2 which must be selected internal to the module. Logic generating lines A, B and C are associated with mode 1 while logic generating lines D, E and F are associated with mode 2. An unused combination of the input signals generated on lines A, B and C is decoded at 6 when it is desired to select mode 2. Decoding the lines A, B and C to select mode 2 effects mode selection without the use of an additional input line or pin connection. This technique can be applied to discriminate between many operating modes, so long as the driving signals have an unused state and are separable such as to allow decoding internally on the module.

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