JTAG TESTING OF BUSES USING PLUG-IN CARDS WITH JTAG LOGIC MOUNTED THEREON

摘要

The plug-in JTAG test card 200 includes a JTAG boundary scanning circuit element 230 used to drive JTAG test data onto a portion of the buses 170, 195 that are connected to the slots 160, 180, 190 of the peripheral device. One or more JTAG plug-in test cards 200 may be used to identify the integrity of each of the point-to-point connections on buses 170, 195 that are disconnected in the plug-in slots of the peripheral. In a preferred embodiment, the plug-in test cards 200 are scanned test buffer circuit elements 230 such that an inexpensive plug-in card can be used for JTAG testing at the production level for multiple motherboards 600. It stimulates either a dual inline memory module (DIMM) or a single inline memory module (SIMM), which includes) but does not contain a real memory chip. In a particularly preferred embodiment, for example, the JTAG boundary scan test buffer circuits 230 of the SN74ABT825 are used as test circuits rather than as their own intended connection circuits.