I encountered a strange problem, please help me.

qd0090

I encountered a strange problem, please help me. [Copy link]

I was debugging a program recently and found that no matter how I adjusted it, it was not correct. Then I measured the clock and found that the amplitude of the crystal oscillator dropped to 1V (normal is about 4V)
. I changed the program and found that it was normal.
In addition, there is no problem with my pin configuration.

In addition, I output a signal to two ports, similar to:
out_1<=S_1;
out_2<=S_2;
but I found that I can measure out_1 but not out2_2;

I think the problem is very strange and unreasonable, haha.

I now suspect that it is a problem with the ise settings. Has anyone encountered the same problem?
Please advise!

linghuchong001

From your description, it seems that the clock is not buffered and the load is too heavy. The reason why the signal disappears may be that the program is not written correctly and some logic has been optimized away.