scan chain scan_out sharing?

[mooney]

scan_out sharing with functional IO needs a mux before the output cell, there's also a boudary scan cell equipped for the output cell, should I put the mux before the boundary cell or after the boundary cell along the signal path from core to IO cell?

 

[dft_guy]

The mux should be before the boundary cell - according to spec, the boundary cells need to be just inside the pads...

John
DFT Digest

 

[bharat_in]

@dft_guy
Can you please tell, which spec are you talking about?

 

[funzero]

I think , you should place an mux before boundary-scan cell io.

 

[rameshsuthapalli]

Hi,

You have to place that mux before that boundary scan cells. since there should not be any logic cells except the pad after tha BS cells.it is according to the IEEE std 1149(which is ment for JTAG).

regards,
ramesh.s

 

[dft_guy]

IEEE 1149.1 spec. I'm almost sure it specifies something like that. I'll have to check. But regardless, it defeats the purpose to put boundary scan logic inside other functions.

John
DFT Digest

 

[mooney]

thanks

I got clear about it. edaboard is really a great place to learn from the experienced !