ScanWorks^® JTAG Hardware

Miscellaneous JTAG Hardware Accessories and Cables

The standard cables needed to connect JTAG controllers, pods and buffer boards to a UUT come as part of the various ScanWorks hardware kits or they can be acquired individually as replacements or spares.

Because there is no standard connector type or pin-out for IEEE 1149.1 JTAG TAP connectors, many different types of cables are used by board designers. And since ASSET can not possibly stock cables for all applications, the cables that ASSET provides conform to the ScanWorks standard pin-outs. The JTAG TAP signal cables that come with the PCI-100 and PXI-100 controllers conform to a ScanWorks standard 14-pin header pin-out, while the cables for the PCI-400 have a ScanWorks standard 20-pin header format to accommodate the discrete IO signals that accompany each PCI-400 test port. An adapter is provided with the PCI-400 Kit to convert the 20-pin header pin-out to the 14-pin header pin-out if the discrete IO signals are not used. For other applications, the user must adapt the cables to the specific UUT.

There are two options for adapting ScanWorks cables to a UUT:

1. Remove the cable connector that came with ScanWorks and replace it with the appropriate connector for the UUT. This provides the least impedance mismatch and is recommended for applications that require the fastest TCK possible.
2. For systems where high throughput is not required and a lower TCK frequency can be tolerated, an adapter cable can be used. This adapter cable should be as short as possible and a careful analysis of its JTAG signal integrity should be done.

Demonstration Board

ASSET's ScanLite demonstration board is used for JTAG training purposes or as a known-good UUT when troubleshooting a problem with the interface to a UUT. ScanLite demonstrates the primary JTAG test applications of ScanWorks, including scan path verification, interconnect testing, memory access verification, cluster testing, PLD programming and flash memory programming. Complete design information such as schematics and layout data, as well as a completed ScanWorks project are provided with ScanLite.