XBST vs EBST - Are there really three cases?

Discuss the generic proposals for SJTAG
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Ian McIntosh
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XBST vs EBST - Are there really three cases?

Post by Ian McIntosh » Sun Jun 08, 2008 8:38 pm

The White Paper (and several presentations) make reference to External BST and Embedded BST as the two schemes for providing a Test Manager to the Unit Under Test:
Image
I'm happy enough with the description of the External case, but I'm becoming increasingly dissatisfied with the Embedded one. As shown, only the Test Controller is embedded, as this falls quite a way short of what my interpretation of the word "Embedded" usually implies. The accompanying text usually makes some reference to the case where the Test Manager is also embedded, but this seems to almost be an off-hand comment.

The reason I think there needs to be a distinction is that which of these latter two cases is used would seem to have a significant bearing on the software tooling.
I expect that from a tool vendor's perspective, the embedded controller case looks little (if at all) different from the external case; the transport to the Test Controller being managed at the hardware abstraction level.
For the "fully embedded" case, while tests, etc., may be developed off-line using the same tooling as above, there is then the issue of migrating the vectors and implementing the host execution.

Whatever the reality regarding the tooling, it seems to me that the "Embedded Controller" and "Embedded Manager" scenarii are sufficiently different to warrant distinction.

User avatar
Ian McIntosh
SJTAG Chair
Posts: 415
Joined: Mon Nov 05, 2007 11:49 pm
Location: Leonardo, UK
Contact:

Re: XBST vs EBST - Are there really three cases?

Post by Ian McIntosh » Sun Mar 01, 2009 9:03 pm

In response to my own thoughts presented in the above post I prepared an alternative representation to show the three configurations that I believe exist:
XBSTvsEBST2.png
I think this illustration gets my thoughts across more readily than the words do!
Ian McIntosh
Testability Lead
Leonardo MW Ltd.

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