JTAG TAP controller TDO pin

[sunidrak]

I am working on JTAG TAP controller in which TDO pin is a tri state . What is the advantage of Tri state TDO pin in TAP controller plz expalin I need badly

 

[ads-ee]

maybe to allow bypassing a faulty part in a JTAG chain to allow further testing comes to mind. Then you can jumper TDI to TDO of that part if it's not working correctly.

 

[jt_eaton]

I am working on JTAG TAP controller in which TDO pin is a tri state . What is the advantage of Tri state TDO pin in TAP controller plz expalin I need badly

You can drive multiple taps and have them share to TDO pin. You do need to be able to select one tap at a time.


John Eaton