Method and apparatus for processor emulation

a processor and serial scan technology, applied in the direction of detecting faulty computer hardware, error detection/correction, instruments, etc., can solve the problems of requiring thousands or hundreds of thousands of shift operations to fully test the circuit, time-consuming patterns into and out of the circuit being tested, and extremely long test time for an ic manufacturing tes

Inactive Publication Date: 2006-12-14
TEXAS INSTR INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Depending on the complexity of the circuit, potentially thousands or hundreds of thousands of shift operations may be required to fully test the circuit.
Having to repeat a shift operation multiple times to transfer test data patterns into and out of the circuit being tested is time consuming.
This test time is extremely long for an IC manufacturing test.
This test time is extremely long for an IC manufacturing test.
In addition, the system may contain 1000 additional ICs of similar complexity as the one tested.
In addition, the system may contain 1000 additional ICs of similar complexity as the one tested.

Method used

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  • Method and apparatus for processor emulation
  • Method and apparatus for processor emulation
  • Method and apparatus for processor emulation

Examples

Experimental program
Comparison scheme
Effect test

case 1

[0124] Case 1 is illustrated in FIG. 10a and occurs when the length of the DISR and DOSR are exactly the same. In FIG. 10a, the DISR and DOSR are both 4-bits in length. During test operations, the BIOS inputs shift in and update (UP) control into DISR and capture (CP) and shift out control to the DOSR while the TAP is in the SHIFTDR state. The test involves repeating the steps of; (1) shifting a 4-bit test pattern from the test bus controller into the DISR, (2) updating the 4-bit test pattern and inputting it to the combinational circuit, (3) capturing the 4-bit output response from the combinational circuit into the DOSR, and (4) shifting out the captured 4-bit response pattern to the test bus controller for processing.

[0125] The update control input to the DISR from the BIOS occurs during the TCK bus cycle following the TCK bus cycle that shifts the last serial test bit (bitI) into the DISR. The capture control input to the DOSR from the BIOS occurs on the TCK bus cycle following ...

case 2

[0126] Case 2 is illustrated in FIG. 10b and occurs when the length of the DISR is greater than the length of the DOSR. In FIG. 10b, the DISR is 4-bits in length and the DOSR is 2-bits in length. Testing is accomplished the same way as described in case 1, and involves repeating the steps of; (1) shifting a 4-bit test pattern from the test bus controller into the DISR, (2) updating the 4-bit test pattern and inputting it to the combinational circuit, (3) capturing the 2-bit output response from the combinational circuit into the DOSR, and (4) shifting out the captured 2-bit response pattern plus two bits of dummy response patterns (X) shifted into the DOSR from a fixed logic level input to the serial input of the DOSR. As the 2-bit response pattern is shifted out of the DOSR, the fixed dummy bits (X) are shifted into the 2-bit DOSR and shifter out to the test bus controller immediately after the 2-bit response pattern. The test bus controller receiving the serial 2-bit response patt...

case 3

[0128] Case 3 is illustrated in FIG. 10c and occurs when the length of the DISR is less than the length of the DOSR. In FIG. 10c, the DISR is 2-bits in length and the DOSR is 4-bits in length. Testing is accomplished the same way as described in case 1 except that the BIOS additionally inputs control to the DISR to provide wait states during the shift in process. Testing of case 3 involves repeating the steps of; (1) shifting a 2-bit test pattern from the test bus controller into the DISR, (2) suspending the shift in operation to the DISR for two wait states or TCK bus cycles, (3) updating the 2-bit test pattern and inputting it to the combinational circuit, (4) capturing the 4-bit output response from the combinational circuit into the DOSR, and (5) shifting out the captured 4-bit response pattern to the test bus controller for processing. The wait states are represented by dummy bits (X) which are inserted by the test bus controller, but ignored by the BIOS during step (2) above. ...

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PUM

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Abstract

An emulator for emulating operations of data processing circuitry normally connected to and cooperable with a peripheral circuit includes serial scanning circuitry connectable to the peripheral circuit. The serial scanning circuitry provides to and receives from the peripheral circuit signals which would normally be provided and received by the data processing circuitry. The serial scanning circuitry is connectable to an emulation controller for transferring serial data between the emulation controller and the emulator. The serial scanning circuitry includes a first state machine having plural states controlling the transfer of serial data. The emulator further includes control circuitry connected to the serial scanning circuitry and connectable to the emulation controller. The control circuitry, when connected to the emulation controller, effects the providing and receiving of signals and the transferring of serial data between the emulation controller and the emulator continuously without interruption while the first state machine remains in one state.

Description

CROSS REFERENCE TO RELATED DOCUMENTS [0001] This application is a divisional of application Ser. No. 10 / 771,269, filed Jan. 3,2004, allowed Dec. 29, 2005; [0002] which was a divisional of application Ser. No. 09 / 746,590, filed Dec. 21, 2000, now U.S. Pat. No. 6,779,133; [0003] which was a divisional of application Ser. No. 09 / 430,932, filed Nov. 19, 1999, now U.S. Pat. No. 6,189,115; [0004] which was a divisional of application Ser. No. 08 / 885,464, filed Jun. 27, 1997, now U.S. Pat. No. 6,006,343; [0005] which was a continuation of application Ser. No. 08 / 391,291, filed Feb. 21, 1995, now U.S. Pat. No. 5,687,312; [0006] which was a continuation of application Ser. No. 08 / 101,503, filed Jul. 30, 1993, now abandoned. [0007] The following documents include subject matter which is related to the subject matter of this application. These documents have been assigned to the assignee of this application, and are incorporated herein by reference: TI-14141AU.S. Serial No. 07 / 846,459 abandon...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G01R31/28G06F11/00G01R31/317G01R31/3185G06F11/26
CPCG01R31/31705G01R31/31715G06F11/261G01R31/318544G01R31/318555G01R31/318533
Inventor WHETSEL, LEE D.
Owner TEXAS INSTR INC
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