Circuit testing with ring-connected test instruments modules
First Claim
1. A test apparatus comprising a plurality of test instruments synchronized to a global clock and connected to each other through a ring bus, one of the instruments having a programmable device for issuing a trigger signal over the ring bus to the other instruments,wherein each of the test instruments has a global clock counter that is reset upon receipt of a synchronization signal issued by the global clock, and incremented at each global clock cycle;
- andwherein the trigger signal includes a global clock number and at least one of the other instrument is programmed to be triggered when a difference between its global clock counter and the global clock number is equal to a predetermined value.
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Abstract
Method and apparatus for circuit testing with ring-connected test instrument modules. A system for controlling one or more test instruments to test one or more integrated circuits includes a master clock and a controller. The test instruments are connected to form a communication ring. The master clock is connected to each test instrument and provides a clock signal to the one or more test instruments. The controller is connected to the communication ring and is configured to align counters of test instruments to derive a common clock time value from the clock signal. The controller is further configured to generate and send data words into the communication ring to carry the data words to each test instrument. The data words includes at least one data word specifying a test event to be performed, a common clock time value, and at least one of the test instruments.
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Citations
20 Claims
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1. A test apparatus comprising a plurality of test instruments synchronized to a global clock and connected to each other through a ring bus, one of the instruments having a programmable device for issuing a trigger signal over the ring bus to the other instruments,
wherein each of the test instruments has a global clock counter that is reset upon receipt of a synchronization signal issued by the global clock, and incremented at each global clock cycle; - and
wherein the trigger signal includes a global clock number and at least one of the other instrument is programmed to be triggered when a difference between its global clock counter and the global clock number is equal to a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A test apparatus, comprising:
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a main module including a global clock; a first module synchronized with respect to the global clock and having a global clock counter that is incremented each global clock cycle; a second module synchronized with respect to the global clock and having a global clock counter that is incremented at each global clock cycle; a third module synchronized with respect to the global clock and having a global clock counter that is incremented at each global clock cycle; and a ring bus connecting the first module, the second module, and the third module, wherein each of the first, second and third modules includes a programmable device that is programmed to;
(i) issue trigger instructions having various trigger types over the ring bus;
(ii) monitor the trigger instructions for a certain trigger type; and
(iii) be triggered by a trigger instruction having said certain trigger type. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of testing an electronic device using an apparatus having a plurality of test instruments connected to each other through a ring bus, comprising the steps of:
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synchronizing the test instruments to a global clock; resetting a global clock counter at each of the test instruments upon synchronization; incrementing the global clock counter at each of the test instruments at each global clock cycle; issuing trigger commands over the ring bus; at each test instrument, receiving the trigger commands over the ring bus and passing on the trigger commands over the ring bus except for the trigger commands originated by said test instrument; and at each test instrument, supplying test signals to the electronic device with reference to the trigger commands issued for said test instrument and the global clock counter of said test instrument. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification