ELECTRONIC DEVICE

摘要

An electronic device (100) has a plurality of subdevices (120a, 120b) with each subdevice (120a; 120b) coupled to a test interface (140a; 140b). The test interfaces (140a, 140b) are arranged in a chain of test interfaces (140) by coupling the TDO contact (142b) of a predecessor test interface (140a) to the TDI contact (141b) of a successor test interface (140b) in the chain (140). In addition, at its beginning, the chain (140) is extended with a boundary scan compliant test interface (160) for testing other parts of electronic device (100). Both the TDO contact (142b) of the last test interface (140b) in the chain (140) as well as the TDO contact (162) of test interface (160) are coupled to a bypass multiplexer (102), thus yielding two possible routes from test data input (110) to test data output (112): through the full chain (140, 160) or through test interface (160) only. Consequently, electronic device (100) can be tested or debugged as a macro device or as a collection of subdevices (120a, 120b).