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:
Jun. 06, 2006
Filed:
Feb. 06, 2001
Lane Hauck, San Diego, CA (US);
Lane Hauck, San Diego, CA (US);
Cypress Semiconductor Corporation, San Jose, CA (US);
Abstract
A method and apparatus for automatically detecting the memory size of a serial peripheral interface (SPI) device. Specifically, the present invention describes an SPI interface circuit including a memory controller chip, an EEPROM, a sensing circuit, and a pulldown resistor. In one embodiment, a 'READ' command from the controller to the SPI device is sent in a first byte of information transferred between the controller and SPI device. The data Input/Output (D-IO) pin is then driven low for the second byte of information. Next, the D-IO pin is floated and the pin assumes a logic '0' level due to a pulldown resistor. Subsequently, a sensing circuit can detect when and if a non-zero data value passes from the SPI device to the memory controller chip to determine the memory size of the SPI device or the absence of an SPI device.