Hi,
I´m thinking about using the internal TAP controller and the boundary scan chain of the virtex devices to test our board. Currently we using special bitstreams for this purpose. As I found in the manual I only have to issue the EXTEST command and feed data to the 3bit/per IO chain. Is this the right order? Or should the first command the SAMPLE command and then - when all data is written - the EXTEST command?
Some advices would be welcome ;-)
Thank you!
kind regards, thomas
right
you can do it all by using EXTEST command alone, if you know safe values for all iopads. in case you dont and dont wanna blow your circuitry you can use SAMPLE to pre-sample the current values and then use that readback to construct your new data for EXTEST command.
in your case I would say EXTEST alone is sufficent you can sense and force any FPGA io pin and test or program any circuits connected to the FPFA
Antti
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