摘要:
In a semiconductor integrated circuit, power source wiring for supplying power supply voltage to a plurality of flip flop circuits, and power source wiring for supplying different power supply voltage to a combinational circuit are provided individually, so that the power supply to the flip flop circuits and the power supply to the combinational circuit can be performed separately from, and independently of, each other. During shift operation in scan testing, the power supply voltage to the combinational circuit is set to a low voltage or cut off, thereby suppressing the amount of power consumed by the combinational circuit portion during the shift operation. At the same time, the power supply voltage to the flip flop circuits is set to a high voltage during the shift operation.
摘要:
A method of designing a semiconductor integrated circuit includes steps of selecting a pair of scan registers to be connected as a scan chain and calculating a beeline distance on hardware from each output terminal of the scan register at the front stage to a scan data input terminal of the scan register at the rear stage. The method further includes steps of selecting the output terminal of the scan register at the front stage having a minimum beeline distance on the basis of the above calculation; determining to connect the selected output terminal with the scan data input terminal of the scan register at the rear stage; and forming the scan chain by connecting each pair of scan registers by using the output terminal determined in the previous step.
摘要:
Elements of a combinational circuit are divided into plural groups. The output from a terminal Q is fixed at shifted timing in flip-flop circuits belonging to each of groups X, Y and Z resulting from this grouping. With the outputs from the terminals Q of the flip-flop circuits thus fixed, an operation of a shift mode is carried out. When the operation of the shift mode is completed, a hold releasing operation and a capture operation are carried out with respect to each of the groups of the flip-flop circuits. For example, the hold releasing operation is carried out when one clock is at a high level with the capture operation carried out when the clock is at a low level, or the hold releasing operation is successively carried out with respect to each of the groups and then the capture operation for capturing a data signal is carried out with respect to each of the groups.
摘要:
All untestable delay faults are hardly calculated. Thus, when the fault coverage of an test sequence for a delay fault is calculated, the fault coverage is not calculated without excluding the number of untestable faults. Accordingly the fault coverage does not correctly represent a test quality.The delay faults are partly selected to analyze how many untestable delay faults exist among the selected delay faults. Thus, the, number of untestable delay faults included all the delay faults are estimated. Thus, a method for evaluating a delay fault test quality for calculating the fault coverage that correctly represents the test quality by using this value is provided.
摘要:
In a semiconductor integrated circuit, power source wiring for supplying power supply voltage to a plurality of flip flop circuits, and power source wiring for supplying different power supply voltage to a combinational circuit are provided individually, so that the power supply to the flip flop circuits and the power supply to the combinational circuit can be performed separately from, and independently of, each other. During shift operation in scan testing, the power supply voltage to the combinational circuit is set to a low voltage or cut off, thereby suppressing the amount of power consumed by the combinational circuit portion during the shift operation. At the same time, the power supply voltage to the flip flop circuits is set to a high voltage during the shift operation.
摘要:
In a semiconductor integrated circuit, power source wiring for supplying power supply voltage to a plurality of flip flop circuits, and power source wiring for supplying different power supply voltage to a combinational circuit are provided individually, so that the power supply to the flip flop circuits and the power supply to the combinational circuit can be performed separately from, and independently of, each other. During shift operation in scan testing, the power supply voltage to the combinational circuit is set to a low voltage or cut off, thereby suppressing the amount of power consumed by the combinational circuit portion during the shift operation. At the same time, the power supply voltage to the flip flop circuits is set to a high voltage during the shift operation.
摘要:
Design data including circuit data on a test point and information about a test mode, which has been attached to the test point, is inputted to an apparatus for designing a semiconductor integrated circuit. A design data code analysis unit in a data input unit performs the code analysis of the design data and, after the code analysis, the resulting design data is stored by a database storage unit in a storage device. A test point deletion unit receives the test mode specified from the outside and deletes data on an unnecessary test point from the design data stored in the storage device. The design data which does not include the unnecessary test point is outputted from a data output unit. Accordingly, even when the test mode is changed, there is no need to calculate the test efficiency again in response to each change or add the step of inserting a new test point.
摘要:
A path under test is selected from a semiconductor integrated circuit that has been designed by a scan method. A test pattern is generated for the selected path so that the path is sensitized and a signal, passing through the path, changes its level at a time before or after a capture clock pulse is input to the circuit. Next, the test pattern generated is transformed into a normal scan pattern. Also, an expected output value, which should result from the test pattern input, is obtained. Then, the test pattern is input to the path under test and the resultant output value is compared to the expected value. In this manner, the path can be tested in such a manner as to see whether or not any hold error will occur.
摘要:
Elements of a combinational circuit are divided into plural groups. The output from a terminal Q is fixed at shifted timing in flip-flop circuits belonging to each of groups X, Y and Z resulting from this grouping. With the outputs from the terminals Q of the flip-flop circuits thus fixed, an operation of a shift mode is carried out. When the operation of the shift mode is completed, a hold releasing operation and a capture operation are carried out with respect to each of the groups of the flip-flop circuits. For example, the hold releasing operation is carried out when one clock is at a high level with the capture operation carried out when the clock is at a low level, or the hold releasing operation is successively carried out with respect to each of the groups and then the capture operation for capturing a data signal is carried out with respect to each of the groups.
摘要:
First, in the step of analyzing integrated circuit information, integrated circuit information is retrieved and the structure of the circuit is analyzed, thereby creating routing information for each functional block. Next, in the step of analyzing pin allocation information, pin allocation information, including input and output pin connection information for the functional block, is retrieved and the contents thereof are analyzed, thereby creating machine-readable pin combination information. The input pin connection information represents which input pin of the functional block should be connected to each external test data input pin. The output pin connection information represents which output pin of the functional block should be connected to each external test data output pin. Then, in the step of outputting testable integrated circuit information, information about a test data input or output circuit is added to the routing information, which has been analyzed in the step of analyzing integrated circuit information, based on the pin combination information, thereby outputting testable integrated circuit information.