A built-in self-test for analog reconfigurable filters implemented in a mixed-signal configurable processor

This work introduced a new BIST scheme under a functional test approach. It solves the problem of determining in-field the specifications of lowpass filters embedded in PSoC1 devices with zero hardware overhead. The user can implement the BIST we propose here because it just requires the information and resources freely offered by the manufacturer, the nominal specifications of the filter, and its location within the resources array of the chip. It consists of a software routine that reconfigures the resources available in the device to synthesize all the circuitry needed for the test: stimuli generation, filter response measurement and analysis, data processing, and a communication interface to output the test results. The proposal is based on the transient response analysis method (TRAM), a test strategy for analog filters used to determine the functional parameters of the circuits under test. The BIST performance was evaluated by comparing it against frequency response and TRAM measurements. The laboratory results showed low errors and good repeatability, validating the proposal.