The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 06, 2009
Filed:
Dec. 13, 2005
David A. Asson, Palo Alto, CA (US);
James Macarthur, Santa Clara, CA (US);
David A. Asson, Palo Alto, CA (US);
James Macarthur, Santa Clara, CA (US);
Altera Corporation, San Jose, CA (US);
Abstract
A mask programmable integrated circuit includes a read only memory (ROM), a random access memory (RAM), and a controller. The controller couples to the ROM and RAM. The controller senses a reset condition and, in response, directs a clear of the RAM or a preload of contents of the ROM to the RAM. The preload can be performed after a successful self-test of the RAM is achieved. The RAM has a variable word length and depth size and can be configured to operate in one of many modes. The integrated circuit further includes a first and a second multiplexer (MUX). The first MUX is interposed between the RAM and the ROM, and selectively couples either the ROM data or the built-in self-test (BIST) data to the first MUX output. The second MUX is interposed between the first MUX and the RAM, and selectively couples either the output of the first MUX or a (synchronous or asynchronous) data input to the RAM. With the preload feature, the invention can emulate a ROM, a preloaded RAM, or look-up table logic functions as well as conventional RAM. Further, BIST allows for testing of the RAM without the needs for external support.