Asynchronous control of memory self test
View Patent ↗A memory logic built-in self-test (“BIST”) includes slow speed controller-to-collar signals, while allowing collars to test memories at full speed. A controller is configured to include control features and address, data, read/write, output evaluation, and redundancy calculation values are configured within the collars. The controller is further configured to handle scheduling of the collars and diagnostics interfacing. In addition, the collars are configured to allow BIST testing to be run serially, in parallel, or in groups. Collars are also configured to send diagnostic results back to the controller based on the initialization of the respective collars, thus providing a central interface for the diagnostics results.
1. A memory built-in self-test (“BIST”) configuration on an integrated circuit chip, the configuration comprising:
a plurality of memories, each memory having associated memory logic and at least two memories comprising memories of differing types and at least two memories comprising memories having different clock domains; and
a controller, configured to asynchronously control testing of the plurality of memories during BIST,
the controller further comprising,
a scheduling element configured to group the plurality of memories into a plurality of testing sets, and configured to select a testing set of the plurality of testing sets for testing memories in the testing set in a predetermined order; and
a diagnostic element configured to determine whether a memory in the testing set of the plurality of memories failed.
2. The configuration of claim 1 , wherein the controller further comprises an enable element configured to transmit an enable signal to enable testing of a selected memory of the plurality of memories.
3. The configuration of claim 2 , wherein the enable element is configured to generate an enable signal using a test signal from a test clock, the test clock configured to operate at a slower speed than a system clock.
4. The configuration of claim 3 , wherein each memory and associated memory logic operate at a speed corresponding to a system clock signal from the system clock.
5. The configuration of claim 3 , wherein the system clock generates a system clock signal in a range of 50 to 100 times greater than a speed of the test clock signal.
6. The configuration of claim 1 , wherein memory logic for each memory further comprises logic elements configured to establish timing synchronization.
7. The configuration of claim 1 , wherein the scheduling element is configured to generate a test done signal for transmitting through a test access port, the test done signal indicating testing of the plurality of memories is completed.
8. The configuration of claim 1 , wherein for each memory the associated memory logic of the plurality of memories comprises a collar.
9. The configuration of claim 1 , wherein the testing set comprises at least one memory.
10. The configuration of claim 1 , wherein the diagnostic element is further configured to identify which memory in the testing set of the plurality of memories failed.
11. A method for conducting a built-in self-test (“BIST”) for a plurality of memories in an integrated circuit chip, the plurality of memories comprising at least two memories of differing types and at least two memories having different clock domains, the plurality of memories further comprising associated memory logic, each associated memory logic comprising a collar, the method comprising:
associating memories of the plurality of memories into a plurality of testing sets, each testing set comprising at least one memory;
selecting a testing set of the plurality of testing sets to test each memory in the testing selected testing set;
generating an enable signal at a slow signal speed relative to the signal operation speed of the collar, the enable signal to begin testing of a currently selected memory in the selected testing test;
receiving a diagnostic error signal in response to the currently selected memory in the selected testing set having a failure; and
receiving a test complete signal from the currently selected memory in response to its testing being completed.
12. The method of claim 11 , further comprising generating another enable signal to test the next memory in the testing set in response to receiving the test complete signal and having to test additional memories in the selected testing set.
13. The method of claim 11 , further comprising generating a BIST complete signal in response to completion of testing of each testing set of the plurality of testing sets.
14. The method of claim 11 , wherein associating the memories further comprises:
determining an order for testing the plurality of memories; and
determining a predetermined number of memories to be tested at a time in view of at least one testing constraint.
15. The method of claim 14 , wherein a testing constraint comprises power drawn by the chip.
16. The method of claim 11 , wherein receiving a diagnostic error signal further comprises identifying a particular failure in the currently selected memory.
17. A system for conducting a built-in self-test (“BIST”) for a plurality of memories in an integrated circuit chip, the plurality of memories comprising at least two memories of differing types and at least two memories having different clock domains, the plurality of memories further comprising associated memory logic, each associated memory logic comprising a collar, the system comprising:
means for associating memories of the plurality of memories into a plurality of testing sets, each testing set comprising at least one memory;
means for selecting a testing set of the plurality of testing sets to test each memory in the testing selected testing set;
means for generating an enable signal at a slow signal speed relative to the signal operation speed of the collar, the enable signal to begin testing of a currently selected memory in the selected testing test;
means for receiving a diagnostic error signal in response to the currently selected memory in the selected testing test having a failure; and
means for receiving a test complete signal from the currently selected memory in response to its testing being completed.
18. The system of claim 17 , wherein the means for generating generates another enable signal to test the next testing set in response to receiving the test complete signal from the currently selected testing set.
19. The system of claim 17 , further comprising a means for generating a BIST complete signal in response to completion of testing of each testing set of the plurality of testing sets.
20. The system of claim 17 , wherein the means for associating the memories further comprises:
a means for determining an order for testing the plurality of memories; and
a means for determining a predetermined number of memories to be tested at a time in view of at least one testing constraint.
21. The system of claim 20 , wherein the means for determining an order for testing further comprises a means for determining power drawn by the chip.
22. The system of claim 17 , wherein the means for receiving a diagnostic error signal further comprises a means for identifying a particular failure in the currently selected memory.