Indefinite states of State Machine - VHDL

Hi deded84,

I’m not sure if I understand you right. But if your code sometimes works and sometimes not, it sounds like metastability. Is the external signal synchronized in by flip flops? You should always use synchronizers for external asynchronous signals.

Here is a good paper about this topic:

http://www.altera.com/literature/wp/wp-01082-quartus-ii-metastability.pdf?gsa_pos=9&wt.oss_r=1&wt.oss=metastability

Greets

Sim