jdhar
Full Member level 5
Hi,
I wish to build a JTAG interface for my FPGA projects. Currently, I have the 25 pin parallel port cable going to a header on my board with an FPGA on it, and then level converting circuitry to shift it down to 3.3V from 5V. However, the problem with this is that 1) Extra circuitry required on the board just for JTAG connection, and 2) I can only use one board at a time. So, I would like to build another board that takes the 25-pin parport cable in one end, and then 2 or 3 smaller headers (5x2) that can connect to multiple boards. these headers need to supply 2 sets of signals - one 'hard' JTAG that connects to the JTAG signals on the FPGA, and one 'soft' JTAG set that connects to user-defined signals on the FPGA. The soft JTAG chain is used for Nexus 5001 communication to any processors etc.. on the FPGA's.
How would I go about doing this? Anyone who has any knowledge of Protel's nanoboard or LiveDesign evaluation board should be able to help here. Can I just connect the TDO of one header to the TDI of the next and so on?? will this work for the soft JTAG chain also?
Thank you, Jai.
I wish to build a JTAG interface for my FPGA projects. Currently, I have the 25 pin parallel port cable going to a header on my board with an FPGA on it, and then level converting circuitry to shift it down to 3.3V from 5V. However, the problem with this is that 1) Extra circuitry required on the board just for JTAG connection, and 2) I can only use one board at a time. So, I would like to build another board that takes the 25-pin parport cable in one end, and then 2 or 3 smaller headers (5x2) that can connect to multiple boards. these headers need to supply 2 sets of signals - one 'hard' JTAG that connects to the JTAG signals on the FPGA, and one 'soft' JTAG set that connects to user-defined signals on the FPGA. The soft JTAG chain is used for Nexus 5001 communication to any processors etc.. on the FPGA's.
How would I go about doing this? Anyone who has any knowledge of Protel's nanoboard or LiveDesign evaluation board should be able to help here. Can I just connect the TDO of one header to the TDI of the next and so on?? will this work for the soft JTAG chain also?
Thank you, Jai.