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Altera_Forum
Honored Contributor I
1,367 Views

How to add a buffer chip to JTAG pins

If there are multiple FPGAs on the JTAG chain, altera recommends using JTAG buffer chip on TMS, TCK and TDI pins. I could not find a proper schematic for this. 

Anyone can help?
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Altera_Forum
Honored Contributor I
199 Views

I don't think you'll find a 'proper' schematic detailing this - there are too many options and variations to cover. 

 

I've attached part of a schematic which did just this with 5 Cyclone IV FPGAs on a very large PCB. For reference only (although it did work). 

 

Cheers, 

Alex
Altera_Forum
Honored Contributor I
199 Views

I think you used the voltage supply for the buffer chip as 2.5V. 

I created a similar schematic using the buffer chip 74LVC541ADB but it did not correctly work. The voltage supply for the buffer chip was 3V. 

Please check my thread 

http://www.alteraforum.com/forum/showthread.php?t=53823
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