Browse Prior Art Database

Multiple Image Read Only Storage

IP.com Disclosure Number: IPCOM000076958D
Original Publication Date: 1972-May-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Radzik, LC: AUTHOR

Abstract

The primary purpose of the circuits diagrammed, is to provide a read-only storage (ROS) which can be selectively configured to several different programs. The ROS 1 is shown as a complete matrix of field-effect transistors (FET's) 2, with the drains of all of the FET's 2 of a row connected together to a line 3. Line 3 represents a bit of the word being readout from ROS 1 and its voltage is amplified by a bit-sense amplifier 4 for presentation at an output terminal. Each line 3 is connected to a current source by an FET 5 acting as a current limiter in series with a bit selecting FET 6. A bit select circuit 7 can be set by a bit address on its input to energize the gate of one or more of the FET's 6, to select the bit or bits needed for a readout function, e.g., a serial or parallel readout of word bits.

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Multiple Image Read Only Storage

The primary purpose of the circuits diagrammed, is to provide a read-only storage (ROS) which can be selectively configured to several different programs. The ROS 1 is shown as a complete matrix of field-effect transistors (FET's) 2, with the drains of all of the FET's 2 of a row connected together to a line 3. Line 3 represents a bit of the word being readout from ROS 1 and its voltage is amplified by a bit-sense amplifier 4 for presentation at an output terminal. Each line 3 is connected to a current source by an FET 5 acting as a current limiter in series with a bit selecting FET 6. A bit select circuit 7 can be set by a bit address on its input to energize the gate of one or more of the FET's 6, to select the bit or bits needed for a readout function, e.g., a serial or parallel readout of word bits.

The FET's 2 in each column represent the related bits of a word to be read out and all FET's 2 of a column have their gates connected together by a lead 8. A word select circuit 9 can be set by a word address bus to energize one of the lines 8, to enable conduction in the FET's 2 of a selected one of the columns of the matrix. The FET matrix of ROS 1 is personalized by a selective connection of the sources of FET's 2 to the other terminal, here ground, of the current source.

If it is desired to have two alternative configurations of ROS 1, as for a machine operating program and for a diagnostic program, the FET's 2 representing a "...