Hi all I need to have a counter that when overflows is set to a predefined value and stops counting. Then only an external signal of clear can restart (from 0) the counter.I thought to use the carry out of lpm_counter1 to disable the counter and a DFF to store carry out until a synchronous clear arrives. The carry out is also used as a synchronous set for the counter. From the simulation the DFF does not behave as expected and it changes its output not following its input nor clock... I attach here a screenshot of design and simulation. I would be glad you could give me some suggestions.. Regards
carry_out (the overflow) never goes high because you're clearing the counter before it ever has a chance to, at least in the simulation waveform you show here. Since you're using it as the clock for the dff (a big no-no since you're creating a gated clock; put it on clock enable for the dff instead), the output of the dff is dictated only by the A_clear signal.