Inventors:
Steven Harley Lamphier - St. Albans VT
Kevin George Petrunich - Essex Junction VT
Harold Pilo - Underhill VT
Ronald DeSales Rossi - Swanton VT
Roger Andrew Verhelst - Colchester VT
Paul Stafford Zerr - Gilbert AZ
Assignee:
International Business Machine Corporation
International Classification:
G11C 700
G11C 800
Abstract:
Circuit and method are presented for activating/deactivating a special operational mode at power-on of an integrated circuit device having no industry defined test state and/or dedicated test pin. The operational mode is enabled upon powering on the integrated circuit combined with detection of a predefined pattern of a first logic state and a second logic state clocked in successive cycles within a first standard input signal, such as an output enable signal, for a normal operating mode of the device. Special non-functional processing is then performed, such as reading prestored identification data from the integrated circuit and/or testing the integrated circuit via embedded test circuitry including boundary scan or other diagnostic circuitry. This special operational mode is deactivated upon receipt at the integrated circuit device of a second standard input signal, such as a write signal for a random access memory (RAM) device, of a predefined logic state (e. g. , write enable state).