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).
摘要:
A boundary scan test circuit comprises a plurality of register cells correspondingly to external pins of a semiconductor device, the register cells being coupled together to form a shift register during a test operation mode. The register cells includes a first selector for selecting one of a parallel input data, serial input data and a code signal, a first register for latching the output of the first selector to output a serial data to be input to a succeeding register cell, a second register for latching the output of the first selector, a second selector for selecting the parallel data or the output of the second register to output parallel data. The code signal is determined based on corresponding one of bits of ID code of the semiconductor device. The ID code is output from the register cells without providing an ID code register, resulting in a simple construction of the register cells and a reduced chip area for the semiconductor device.
摘要:
A method for generating improved detection and diagnostic test patterns and for improving the diagnostic resolution of interconnect testing of a circuit is based on the premise that short-circuits are most likely to result from solder bridges between closely adjacent pins. In a first embodiment, an optimal boundary-scan test pattern is generated. In a second embodiment, boundary-scan test diagnosis is enhanced. In a third embodiment, diagnosis of unpowered short-circuit testing is enhanced.
摘要:
A test system for VLSI circuits comprises a VLSI chip having functional inputs (12) and functional outputs (130), circuitry (28) for controlling test operation of the VLSI chip having a test control input (38) and circuitry for storing test data connected to the circuitry (28) for controlling test operation and connected to the functional inputs. A first rank of functional logic elements (16) on the chip connected to the functional inputs (12). Switches (150) selectively connect either the functional inputs (12) or the circuitry (26) for storing test data to the input of the first rank of functional logic elements. A first rank of flip-flops (50) having two data inputs (48,52) and two data outputs (54,58) provide a selectable data path, one of the inputs (52) being connected to the output of the first rank of functional logic elements (16) and the other (48) of the inputs being connected to the inputs of the first rank of functional logic elements. The flip-flops are controlled by the circuitry (28) for controlling test operation. A second rank of functional logic elements (56) on the chip have an input and an output (54,62), the input being connected to one of the first rank of flip-flops (50). There is an output test data storage circuit (32) and switches (180) for selectively connecting either the output of the second rank of functional logic elements (56) or the second output of the first rank of flip-flops to the functional output (130) of the chip.
摘要:
Electronic apparatus comprises at least one sub-assembly, such as a printed circuit board. The sub-assembly includes physically modifiable storage, such as a set of switches or jumper connections, for storing information on the sub-assembly (e.g. type, version number, and modification level). The physically modifiable storage has connections which allow information to be read electronically from the sub-assembly, e.g. by shifting it serially over a shift path.
摘要:
The invention is a method for improving the diagnostic resolution of a boundary-scan interconnect test after the test has been executed. The invention keys on the fact that shorts are most likely to result from solder bridges between closely adjacent pins. After a test has been executed, the captured test vectors are analyzed (step 702) to determine which nets have produced (i.e., captured) identical net signatures. Since each net was originally assigned a unique net ID number, a duplicated number indicates a fault. Nets with common signatures are grouped together (step 904). Each group of nets is then analyzed (steps 908-928) to determine whether a short-circuit is likely to have occurred between any of the nets within the group. It is assumed that only nets which have proximal (radially adjacent) I/O pins are susceptible to short-circuiting. Nets within a group which have radially adjacent I/O pins are marked (step 922) as likely short-circuited nets. The invention may be used to increase the diagnostic resolution of any boundary-scan interconnect test pattern.
摘要:
A method for generating improved detection and diagnostic test patterns and for improving the diagnostic resolution of interconnect testing of a circuit is based on the premise that short-circuits are most likely to result from solder bridges between closely adjacent pins. In a first embodiment, an optimal boundary-scan test pattern is generated. In a second embodiment, boundary-scan test diagnosis is enhanced. In a third embodiment, diagnosis of unpowered short-circuit testing is enhanced.
摘要:
Eine Prüfzelle (2) eines elektronischen Bausteins (1) mit einer Schieberegisterprüfarchitektur (Boundary-Scan) besitzt eine Registerzelle (L3), die mit Hilfe eines Multiplexers (MUX2) mit einem Herstellerdatum (MC) programmierbar ist. Eine Boundery-Scan-Architektur mit derartigen Zellen ermöglicht die Implementierung eines Herstellerregisters, ohne daß auf dem zugehörigen Bausteinkern (4) Platz beansprucht wird.