JTAG support over a broadcast bus in a distributed memory buffer system

US10393805B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Logan I. Friedman · Nyack, US
• Nicholas Rolfe · Hyde Park, US
• Susan M. Eickhoff · Hopewell Junction, US
• Steven R. Carlough · Poughkeepsie, US
• Gary A. Van Huben · Poughkeepsie, US
• Markus Cebulla · Gerstetten, DE
• Walter Pietschmann · Dornstetten, DE

Key dates

• Filing date: Dec 1, 2017
• Grant date: Aug 27, 2019
• Expiry date: Dec 1, 2037

Classification

• Technology area (CPC G): Physics
• CPC primary: G11C29/16
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method, apparatus and system testing a plurality of semiconductor chips in a distributed memory buffer system is provided. Embodiments of the present invention recognize improvements to testing signals through the chip substrate and motherboard. This invention overloads the shared broadcast bus by using it for test purposes rather than its normal mainline function. One of the main components of this invention is the A/C chip. In test mode, the AC chip converts JTAG commands into an internal test format and sends test data over the shared broadcast bus. Each data chip determines whether the scan data is for itself or if it should ignore it. The corresponding data chip then processes the data, and if necessary sends return data back to the address and command chip, where it is converted back into JTAG format and can be seen by the tester.