On-line Boundary-Scan Testing in Service of Extended Products

Boundary-Scan testing has become increasingly popular in the research & development and the manufacturing of modern electronics. Simple boards and complex multi-board systems can effectively be tested using the IEEE-1149.1 standard compliant equipment from the product design phase through to mainstream manufacturing. However, in situations of field-level product failures there have been limited diagnostic choices available. For detailed fault analysis, the product is shipped to a central repair facility, or the fault diagnosis and repair is carried out by field service personnel sent to the site. This paper describes solutions for providing on-line boundary-scan access to remotely located embedded electronics, and may serve as inspiration to the emerging SJTAG (System-JTAG) standard effort. These solutions enable an extended service strategy to be provided for embedded products that require high availability and fault tolerance, or alternatively enable upgrading of the existing set of product features.