fused fpga and jtag

[kcheung]

i would like to know if there is a way max10 fpga can be fused.   I have a board that can no longer be detected with usb blaster ii.      Someone was messing with the board and images.    Now, I can no longer be able to reprogram the fpga.      Is it possible to "fuse" a max10 fpga so that it can not be read or reprogrammed by Usb blaster ii ?

[FvM]

Hi
you are aware of JTAGEN pin?

[kcheung]

There is no change on the pin JTAG_EN.    I want to know if there is someway to stop FPGA JTAG access without a board level change.    

Is there a way that someone had programmed an image that may stop FPGA from accessible through JTAG ?

I have the FPGA replaced and now the board is working.   the USB blaster can program the FPGA again.     

I want to know  any mechanism that could kill the JTAG interface on the Max10.

Thanks

[FvM]

Hi,
if JTAGEN isn't pulled high on the board and someone enabled JTAG pin sharing inadvertently, you loose JTAG access.

[kcheung]

Thanks for the reply. I have the question.

1. I am sure that the JTAGEN is pulled high,

2.  when you mentioned "lose JTAG access",  do you mean momentarily ?  or you mean permanently ?

The symptom I have encountered is that there is no hardware modification and yet,  I lost the JTAG access.      After replacing the FPGA, the USB blaster works and I can program the FPGA again.   

[WZ2]

Hi there,

For max 10, if you don't wanna max10 load the image from cfm, you can pull low the nconfig after power up(ep: you can connect the nconfig to gnd). After you enter the user mode, you can use the programmer to detect the cfm and erase it.

The 'jtagen' may be the reason why you cannot detect jtag line, if you sure it is the reason and wanna solve it, you can pull down the "jtagen" pin. Of course, the way you pull down the nconfig can also solve this problem.

Best regards,

WZ