Programable multi-port memory bist with compact microcode

Abstract

A microcode programmable built-in-self-test (BIST) circuit and method for testing a multiported memory via multiple ports, either simultaneously or sequentially, as directed by a microcode instruction word. The microcode instruction word contains a plurality of executable subinstructions and one bit of information that controls whether the test operations prescribed in the plurality of subinstructions shall be executed in parallel or in series. The executable subinstructions are dispatched by a primary controller to subcontrollers which perform test operations at each port according to the subinstructions. The microcode programable BIST architecture flexibly facilitates the testing of multiple devices, multiported devices, including multiported memory structures and complex dependent multiported memory structures. The BIST supports in-situ testing of the functionality of the memory at wafer, module, and burn-in, as well as system-level testing.