SnM

I am using a 12f629, and sometimes when i connect power to my circuit, it locks up.

After I burn the chip, or let it sit with now power for a while, and then apply power, it runs fine, and lights up an LED I have connected to GPIO,0.
I also have an LED on GPIO,1 and 4. GPIO,2 and 3 are inputs, and the pins are NOT floating. GPIO, 2 has a pull down resistor to ground, GPIO,3 has a pull up resistor (2.2K I believe). And reset is setup for internal only. GPIO,5 is pulled up high with a resistor.

If I remove power, and wait about 2 seconds after the LED fades away, sometimes it will not work correctly. I either get:

1. No LED's light up.
2. LED's connected to GPIO,0 and 4 light up.
3. All LED"s try to light up
4. Or it works normal.

What would cause a PIC to not start up okay? Could it be my power supply???? I am using a .1uF cap across the PIC's power and ground. I attached an image of my power supply.... I am not able to double check it now, since I am no where near it, but I believe that is what it is.

Thinking a bit more about it, the errors occur when I have GPIO,3 low (switch activated).......I don't remember the errors happening when GPIO, 3 starts off high. I have the RESET set for internal, but could that still cause a problem?

Thanks!
Steve

Attached Images

pic-supply.jpg (12.3 KB, 433 views)

Exo

Did you enable the Brown Out fuse ?

SnM

no

Exo

well, try enabling it

SnM

thanks, that helped a lot!!!

avarachan

Hi,

I had the same problem of 12f629 lock out. I found this post about brown out fuse here. It solved the problem. I am writing this just in case any one who needs this info can get it.

Scene: 12f629 with GP0 and 1 as unputs, 2 as output. When I power up, sometimes GP2 starts as high, which i dont want to. Bcz I use GP2 to trigger a switch when GP0 and 1 as comparators give a high out. Again, some times when i Power up, the chip locks out, and no response.

Solution: I was having NOBROWNOUT fuse set. I changed it to BROWNOUT. Every thing is fine now. Thanks a lot, to "EXO"