| 摘要 |
A plug-in JTAG test card (200) includes JTAG boundary scan circuitry (230) which may be used to drive JTAG test data out onto portions of buses (170, 195) connected to peripheral slots (160, 180, 190). One or more of the JTAG plug-in test cards (200) can be used to verify the integrity of each of the point-to-point connections on the buses (170, 195) which terminate in the peripheral plug-in slots. In one advantageous embodiment, the plug-in JTAG test cards (200) simulate a dual in-line memory module (DIMM) or single in-line memory module (SIMM) cards which include scan test buffer circuitry (230) but do not actually include memory chip so that an inexpensive plug-in card (200) can be used to provide JTAG testing at the manufacturing level for multiple motherboards (600). In a particularly preferred embodiment, JTAG boundary scan buffer circuits (230), such as, for example, SN74ABT8245's, are used as test circuits rather than for their intended use as interface circuits.
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