On line PROM handling system

• US 3,969,618 A
• Filed: 11/29/1974
• Issued: 07/13/1976
• Est. Priority Date: 11/29/1974
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Tung, Michael, Mizota, Don Minoru, Scheding, William Lawrence, Sanborn, Alfred Watson, Forte, Jefferson Frank, McNair, Richard Dale, Strubel, John Michael
• Primary Examiner(s): Atkinson, Charles E.
• Application Number:
  US05/528,241
• Time in Patent Office: 592 Days
• Field of Search: 235/153 AC, 340/172.5, 340/173 SP, 340/174 TC, 340/174 SP, 324/73 R, 324/73 AT, 209/72
• US Class Current: 714/719
• CPC Class Codes: G11C 17/14 in which contents are determined by selectively establishing, breaking or modifying connecting links by permanently altering the state of coupling elements, e.g. PROM
• CPC Class Codes: G11C 2029/0403 during or with feedback to manufacture
• CPC Class Codes: G11C 29/50 Marginal testing, e.g. race, voltage or current testing
• CPC Class Codes: G11C 29/50012 of timing
• CPC Class Codes: G11C 29/56 External testing equipment for static stores, e.g. automatic test equipment [ATE]; Interfaces therefor

Abstract

Apparatus for the automatic inspecting, programming and testing of programmable read-only memory (PROM) devices. Under computer control, this PROM Handling System will test a sequence of PROMs against new part specifications, program them in any sequence of bit patterns required by the next piece of machinery on the assembly line, mark the PROM with a four digit part number identifying the bit pattern contained therein, dry the ink in a heated chamber for a fixed amount of time, dynamically test each PROM bit for access time in a hot and cold environment, program and test replacement PROMs for the ones that had failed at any point in the process, sort the PROMs into the correct order as required by the next assembly line machine and output said tested and ordered parts into output sticks for manual delivery or automatically deliver them by a track arrangement to the next machine. The programming apparatus can produce any type of electrical programming pulse and can test the device'"'"'s access speed through the use of programmable circuitry which can be automatically reconfigured by the computer to accomodate the various vendor specifications.

Claims

1. Apparatus for automatically programming and testing a programmable read-only memory (PROM) device of the type having a fuse corresponding to every bit in memory, the selective blowing of said fuses by the application of electrical pulses constituting the programming of said PROM, comprising:

means electrically coupled to said PROM for programming said PROM with a predetermined bit pattern by the selective blowing of said fuses,

means electrically coupled to said PROM for testing the access time required for said PROM to output said bit pattern contained within said PROM after completion of said programming, and

means for transporting said PROM to said means for programming and to said means for testing.

2. The apparatus of claim 1 wherein said means for programming further comprises means for inspecting said PROM prior to programming to dtermine determine said PROM contains a bit pattern corresponding to an unprogrammed PROM.

3. The apparatus of claim 2 wherein said means for transporting further comprises means for supplying a pluraity of PROMs to said means for programming and said means for testing to provide a sequence of PROMs being transported through said apparatus.

4. The apparatus of claim 3 wherein said means for programming further comprises means for marking each of said plurality of PROMs with an individual part number corresponding to the pattern programmed into said PROM.

5. The apparatus of claim 4 wherein said means for testing includes means for ejecting from said apparatus a PROM which has not been successfully inspected, programmed and tested.

6. The apparatus of claim 5 wherein said means for testing further comprises means for controlling the temperature of said PROM being tested.

7. The apparatus of claim 6 wherein said means for programming comprises means, responsive to the ejection of a PROM by said means for testing, for replacing said ejected PROM by initiating the inspecting, programming and marking of a replacement PROM.

8. The apparatus of claim 7 including means responsive to said means for programming for receiving said PROMs from said means for testing and for ordering said PROMs into that sequence that would have prevailed if no PROM had been ejected.

9. A system for programming and testing programmable read-only memory (PROM) devices of the type programmable by electrical pulses, comprising:

programming means for programming said PROM and for subsequently verifying that said PROM contains the bit pattern programmed into it,

means for testing the access time and output state of each memory bit of said PROM,

a computer for transmitting a bit pattern to said programming means for programming said PROM and for providing an identical bit pattern to said means for testing to test said PROM, and

means for transporting said PROM to said programming means, and responsive to the completion of operation upon said PROM by said programming means for transporting said PROM to said means for testing.

10. The apparatus of claim 9 wherein said programming means comprises:

a first random access memory (RAM) for receiving from said computer the bit pattern to be loaded into said PROM,

programming contacts for making electrical contact with the leads of said PROM, and

programming circuits for generating and applying electrical pulses to said PROM through said programming contacts for programming said bit pattern into said PROM.

11. The apparatus of claim 10 wherein said means for testing comprises

a second RAM for receiving said bit pattern from said computer,

testing contacts for making electrical contact with the leads of said PROM, and

testing circuits for comparing the bit pattern received from said computer with said bit pattern programmed into said PROM and received from said PROM through testing contacts, and for testing the access time of each bit of said PROM.

12. The apparatus of claim 10 wherein said means for transporting comprises means for supplying a sequence of PROMs to said programming means.

13. The apparatus of claim 12 wherein said means for testing comprises means for controlling the temperature of said PROM during said testing.

14. The system of claim 13 wherein said means for transporting further comprises first sorting means for receiving PROMs from said means for testing and for ejecting those PROMs that could not be successfully contacted, verified, programmed or tested.

15. The apparatus of claim 14 wherein said computer comprises means responsive to the ejection of a PROM by said first sorting means for transmitting a second bit pattern to said programming means identical to the bit pattern contained in said first RAM during the programming of said ejected PROM.

16. The system of claim 15 wherein said means for transporting comprises second sorting means for receiving PROMs from said first sorting means, for temporarily storing said PROMs and for discharging said PROMs in the order that would have prevailed if no PROM had been ejected.

17. The apparatus of claim 16 wherein said programming means comprises means for marking each PROM with a part number corresponding to the bit pattern programmed into said PROM.

18. The apparatus of claim 9 wherein said means for transporting comprises:

a track for transporting a PROM,

a source of compressed air for propelling a PROM along said track, and

a positioning pin for blocking said track to stop said PROM at said programming means and at said means for testing.

19. A computer controlled method of automatically programming and testing a programmable read-only memory (PROM) comprising the steps of:

first transporting said PROM to a programming station for making electrical contact between all leads of said PROM and said programming station,

programming said PROM according to a pattern provided by said computer to said programming station,

second transporting said PROM to a test station, and

testing said PROM by comparing its contents with a pattern provided by said computer, which pattern is identical to the one used in said programming step, said testing to be performed to test that said PROM is capable of accessing data at a predetermined speed.

20. The method of claim 19 including the step of inspecting said PROM to determine that the contents of said PROM conforms to the specification for an unprogrammed PROM prior to the programming step.

21. The method of claim 20 wherein said transporting step includes transporting an additional device to said programming station upon completion of the programming of a prior PROM to produce a flow of PROMs through said programming and test stations, and

wherein said programming step includes the transmission of an ordered sequence of patterns to said programming station to program said series of PROMs in the order in which they are required to be produced.

22. The method of claim 21 including:

ejecting parts that have not successfully completed said testing step, or have not been successfully verified in said verifying step, and

performing said programming step to program a replacement PROM for each one ejected.

23. The method of claim 22 including the step of sorting said PROM'"'"'s after said ejecting step to order said PROMs into that sequence that would have obtained if no PROMs had been ejected.

24. The method of claim 23 including the step of marking each PROM upon completion of said programming step with a part number identifying said pattern provided by said computer.

25. The method of claim 24 including the step of controlling the temperature of said PROM during said testing step.