Test data compression for system-on-a-chip using extended frequency-directed run-length code

One of the major challenges in testing a system-on-a-chip is dealing with the large volume of test data. To reduce the volume of test data, several test data compression techniques have been proposed. Frequency-directed run-length (FDR) code is a variable-to-variable run length code based on encoding runs of 0s. It is demonstrated that higher test data compression can be achieved based on encoding both runs of 0s and 1s. An extension to the FDR code is proposed and by experimental results its effectiveness in achieving a higher compression ratio is demonstrated.