My board has been designed with BF512 commercial grade. I have a problem with the board. Below around 10 degrees C, it shows abnormal operation. When ambient temp is below 10 degrees C, the BF512 works fine if only the period of reset time lasts for more than 1 sec after power-up. If the period of even 300~400ms makes BF512 fail to operate. How did I check whether BF512 works or not accodring to temperatures? /AMS0 pin was observed. At 25 degrees C, pulses which looks like proper operation comes out from /AMS0. On the other hand, /AMS0 goes high then keeps high at below around 10 degrees C. It is the cause of booting failure. Why? I do not understand. Is there anyone who will advise me about the issue?