SN54ACT8997

The SN54ACT8997 are members of the Texas Instruments SCOPE^TM testability integratedcircuit family. This family of components facilitates testing of complex circuit-board assemblies.

The SN54ACT8997 enhance the scan capability of TI's SCOPE^TM family by allowing augmentation of a system's primary scan path with secondary scan paths (SSPs), which can be individually selected by the SN54ACT8997 for inclusion in the primary scan path. These devices also provide buffering of test signals to reduce the need for external logic.

By loading the proper values into the instruction register and data registers, the user can select up to four SSPs to be included in a primary scan path. Any combination of the SSPs can be selected at a time. Any of the SN54ACT8997's six data registers or the instruction register can be placed in the SN54ACT8997's scan path, i.e., placed between test data input (TDI) and test data output (TDO) for subsequent shift and scan operations.

All operations of the SN54ACT8997 except counting are synchronous to the test clock pin (TCK). The 8-bit programmable up/down counter can be used to count transitions on the device condition input (DCI) pin and output interrupt signals via the device condition output (DCO) pin. The SN54ACT8997 can be configured to count on either the rising or falling edge of DCI.

The test access port (TAP) controller of SN54ACT8997 is a finite-state machine compatible with IEEE Standard 1149.1.

The SN54ACT8997 is characterized for operation over the full military temperature range of 55°C to 125°C.The SN74ACT8997 is characterized for operation from 0°C to 70°C.