Quicklogic Corporation

Shieh Huan Yen

Chihhung Liao

Ket Chong Yap

A programmable logic device (PLD) supports scan testing of configurable logical blocks using scannable word line (WL) shift register (WLSR) chains to enable writes to configurable memory bits while scan test data is input via a scan chain comprising scannable bit line (BL) shift registers (BLSRs). Input test data may be shifted onto BLs to write data into a configurable memory bit when a corresponding WL associated with the configurable memory bit is asserted. Logic blocks may comprise: latch-based configurable memory bits, scannable WLSRs forming a distinct WLSR chain in shift mode and driving corresponding WLs. Each WL, when asserted, enables writes to a corresponding configurable memory bit. A scannable BLSR receives serial scan test vector input in shift mode and drives a corresponding BL coupled to the configurable memory bit to write data to the configurable memory bit when the associated WL is asserted.

Programmable logic device with design for test functionality

An area efficient input terminated readable and resettable configuration memory latch is disclosed. A pull-up network and a pair of pull-down networks operate to set the value of an internal node based, in part, on the state of the input terminated bit line and a word line write input. The internal node is inverted to form the output of the configuration memory latch. A reset line operates to reset the latch and a reset cycle is initiated prior to each write cycle. In some embodiments, the configuration memory latch includes a scan mode input, which, when asserted, facilitates automated testing of a programmable logic device that includes the configuration memory latch. Asserting the scan mode input enables Design for Test functionality. A sensing block is configured to sense the state of the bit when a word line read signal and a read enable signal are both asserted.

Growing community of inventors

Taipei, Taiwan

Shieh Huan Yen