Low Cost CMOS Tester
Another one of those pet projects. As Director of Engineering of a branch office of an ASIC company it was tough to rely on debugging test vectors on a tester 3000 miles away. So we built a very simple tester: just enough the run slow speed static vectors and have this interface with our CAD systems.
I came up with a system based on a PC and which used available parallel interface circuits. See note.

The 128 pin prototype is shown right. This setup was used to develop software for these functions:

  • Test function against simulation output.
  • Iterative signal order (race) dependency test.
  • Vector learn mode.

 

more details on the individual C programs

Of course this is functional testing only: no timing. However in ASICs the usual form of test bugs relates to unknown race conditions and unexpected side effects of bi-directional signals. The final hardware is shown right. Wire wrap load boards with ZIF sockets slotted onto the two connectors shown.

Total hardware cost?: about $200!

last changed: Wednesday, February 08, 2006