Testable Modifications

to Transform Primary Untestable Circuit to the Secondary Testable One

If your circuit is untestable we will calculate how to upgrade your circuit concerning controlability and observability.

Source circuit bits which has good both controlability and observability may be form a part of total (100%). The goal is to expand this part to the nearest of 100%.

The additional HW is the payment for testability:
- additional inputs improve controlability and observability thereof
- additional outputs improve observability only

The Tw-CAD simulates all testable modifications and selects such suboptimal set which reduces additional HW for improving testability in the greatest extent.

It will be pointed out in the testable modifications where to place extra inputs and extra outputs. These are to be used in the test mode only.

The circuit met to our advices is the secondary testable one. We don't enforce to designer in the question how to realize modifications we only help him where it is well to place points to improve testability.