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Spartan3 JTAG interface 3.3V

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System.out

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Hello,

I had built the schematic on the application note XAPP453, pg 8. I could program FPGA, also PROM, but when i did not have the JTAG attached to the board, the PROM was unable to download the bitcode to the FPGA.

Now, i need to fix this issue and i am looking to different circuits, which makes me confused:

:arrow: XAPP453, pg 8
https://www.xilinx.com/support/documentation/application_notes/xapp453.pdf
M{0,1,2} are attched to GND
PROG_B, DONE signal has a pull-up to 2.5V
TMS, TCK, TDI (PROM) are feed directly from JTAG, instead doing so after Rser
3.3V JTAG Port pin names are missing

:arrow: UG332, pg 82
https://www.xilinx.com/support/documentation/user_guides/ug332.pdf
Let's assume we want 3.3V JTAG voltage, the PROG_B and DONE pull-up are to 3.3V (V)
/CF (PROM) looks like an input feeded by /PROGRAM signal, while previous schematic shows /CF as an output. (Where does this /PROGRAM signal come from?)

:arrow: Digilent S3 Board, sheet 4/8
https://www.digilentinc.com/Data/Products/S3BOARD/S3BOARD-sch.pdf
Looks like TCK, TMS, .. are feeded aftr Rser (100ohm and not 68ohm as datasheet states)
There are many other differences to previous schematics

So, the question is if I would like to have an FPGA and a Flash PROM working nicely (program FPGA from the PROM; use boundary scan; ...) which is the best schematic to work with? Maybe do you have a circuit schematic that you know it works for this topic?

Kind regards
 

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