Vicky Ying Ya Wu

US Patent:

20060085708, Apr 20, 2006

Filed:

Oct 20, 2004

Appl. No.:

10/969086

Inventors:

Mitchael Howard - San Jose CA, US
Milind Sonawane - Sunnyvale CA, US
Jonjen Sern - Milpitas CA, US
Vicky Wu - San Jose CA, US

International Classification:

G01R 31/28

US Classification:

714726000

Abstract:

An apparatus includes a register of an integrated circuit for shifting a scan test pattern in response to a scan enable signal. The register includes: a shift input for receiving the scan test pattern; a system logic input for receiving a system logic signal; a clock input for receiving a next clock pulse; a scan enable input for switching the register between a shift mode and a normal mode; a register output for latching the shift input in the shift mode or the system logic input in the normal mode in response to the next clock pulse; and a scan enable gating circuit coupled to the scan enable input for holding the register in the shift mode while the scan enable signal is in the shift mode and immediately following a transition of the scan enable signal from the shift mode to the normal mode until after the register output has latched the shift input in response to the next clock pulse following the transition of the scan enable signal to the normal mode.