The primary function of ScanWorks' boundary-scan controllers is to control how JTAG test vectors are applied to the UUT. The vectors created by ScanWorks are transferred over an internal PC bus to the boundary-scan controller. The controller accepts data and commands from ScanWorks software and manipulates the IEEE 1149.1 JTAG Test Access Port (TAP) signals to accomplish the test or programming activity.

With today’s technology, the PCI bus is the most efficient PC bus for boundary-scan applications. It supports a data throughput rate fast enough to support any test application and it is a very reliable bus. The PXI bus is an extension of the PCI bus and it also is very efficient. Other PC interfaces such as a PC's parallel port or a serial bus can be used but, generally, these are not fast or reliable enough except in special applications. Nevertheless, ScanWorks can be connected to the UUT through a PC's parallel port. In addition, ASSET’s new USB-100 hardware kit maximizes testing and in-system programming flexibility while minimizing total cost-of-ownership. About the size of a pack of playing cards, the new portable, cost-effective controller enables a host of exciting new uses for ScanWorks test stations. When combined with ASSET’s uniquely flexible network licensing, the total cost of board validation is reduced substantially.

ScanWorks has four JTAG controllers:

• PCI Single-Port Boundary-Scan Controller (PCI-100 Hardware Kit)
• PXI Single-Port Boundary-Scan Controller (PXI-100 Hardware Kit)
• PCI Multiport Boundary-Scan Controller (PCI-400 Hardware Kit )
• USB-100 Portable Boundary-Scan Controller (USB-100 Hardware Kit)

Each of these controllers has specific features that are particularly useful for certain applications of JTAG. Taken as a group, the ScanWorks controllers offer features and capabilities for all of the most widespread applications of boundary scan.