Semiconductor device and data processing system

Abstract

The test design cost of a circuit capable of accessing an external memory is reduced. There is included a built-in self-test circuit for use in testing an external memory separately from a memory controller for performing memory control in response to an access request to the external memory capable of being coupled to a memory interface, and a TAP controller is used to control the built-in self-test circuit and referring to a test result. There is adopted a multiplexer for switchably selecting the memory controller or the built-in self-test circuit as a circuit for coupling to the memory interface in accordance with control information externally inputted through the TAP controller. The built-in self-test circuit programmably generates and outputs a pattern for a memory test in accordance with an instruction inputted through the TAP controller, and compares data read from the external memory with an expected value.