SN54ABT8245, SN74ABT8245 SCAN TEST DEVICES WITH OCTAL BUS TRANSCEIVERS

SCBS124D - AUGUST 1992 - REVISED DECEMBER 1996

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features

• Members of the Texas Instruments SCOPE^TM Family of Testability Products
• Compatible With the IEEE Standard 1149.1-1990 (JTAG) Test Access Port and Boundary-Scan Architecture
• Functionally Equivalent to 'F245 and 'ABT245 in the Normal-Function Mode
• SCOPE^TM Instruction Set:
  • IEEE Standard 1149.1-1990 Required Instructions, Optional INTEST, CLAMP, and HIGHZ
  • Parallel-Signature Analysis at Inputs With Masking Option
  • Pseudo-Random Pattern Generation From Outputs
  • Sample Inputs/Toggle Outputs
  • Binary Count From Outputs
  • Even-Parity Opcodes
• Two Boundary-Scan Cells per I/O for Greater Flexibility
• State-of-the-Art EPIC-IIB^TM BiCMOS Design Significantly Reduces Power Dissipation
• Package Options Include Plastic Small-Outline Packages (DW), Ceramic Chip Carriers(FK), and Standard Ceramic DIPs (JT)

  SCOPE and EPIC-IIB are trademarks of Texas Instruments Incorporated.

description

The 'ABT8245 scan test devices with octal bus transceivers aremembers of the Texas Instruments SCOPE^TM testabilityintegrated-circuit family. This family of devices supports IEEEStandard 1149.1-1990 boundary scan to facilitate testing of complexcircuit-board assemblies. Scan access to the test circuitry isaccomplished via the 4-wire test access port (TAP) interface.

In the normal mode, these devices are functionally equivalent tothe 'F245 and 'ABT245 octal bus transceivers. The test circuitry canbe activated by the TAP to take snapshot samples of the dataappearing at the device pins or to perform a self test on theboundary-test cells. Activating the TAP in normal mode does notaffect the functional operation of the SCOPE^TM octal bustransceivers.

Data flow is controlled by the direction-control (DIR) andoutput-enable () inputs. Datatransmission is allowed from the A bus to the B bus or from the B busto the A bus, depending on the logic level at DIR. The output-enable() input can beused to disable the device so that the buses are effectivelyisolated.

In the test mode, the normal operation of the SCOPE^TMbus transceivers is inhibited and the test circuitry is enabled toobserve and control the I/O boundary of the device. When enabled, thetest circuitry can perform boundary-scan test operations as describedin IEEE Standard 1149.1-1990.

Four dedicated test pins control the operation of the testcircuitry: test data input (TDI), test data output (TDO), test modeselect (TMS), and test clock (TCK). Additionally, the test circuitryperforms other testing functions such as parallel-signature analysis(PSA) on data inputs and pseudo-random pattern generation (PRPG) fromdata outputs. All testing and scan operations are synchronized to theTAP interface.

The SN54ABT8245 is characterized for operation over the fullmilitary temperature range of -55°C to 125°C. TheSN74ABT8245 is characterized for operation from -40°C to85°C.

View more information about generic part numbers:SN54ABT8245, SN74ABT8245

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