Can Boundary Scan be used for Analog?

Sep 26, 2008 1 Replies

As I understand, Boundary Scan compliant devices can be used for to make sure you don't have any shorts or opens between boundary scan devices... but what about analog functionality?



For example, if a 1149.1 compliant microcontrollers has a built-in D/ A, can a ATPG test be written such that the full analog swing of the pin can be tested? Or is TDI/TDO restricted to logic levels only and arn't meant for analog testing?



If not, anyone know if the new JTAG standards coming down the road (1149.7, P1587) will have such support? I'd like to use a board test that actually tests some board functionality logic instead of just shorts/opens!


Not really, you can do as much boundary scan operations with a device as there are implemented into it by the silicon vendor. Typically you can read logic level at pins and drive to a logic level or tristate them. Sometimes you can do all that with any pin, sometimes not.

Nothing in the JTAG signals restricts access to some ADC or DAC on the chip, but I have not seen a chip which does that yet. Which does not mean there is none, of course; it is most certainly doable over

1149.1.

Didi

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