put a capacitor to the output of 7805
to filter, otherwise it will oscillate
a 10k pull up resistor for reset pin
and an 100 nF capacitor conected between reset pin and ground to have a stable
start up
----- Original Message -----From: javierfiascheSent: Wednesday, February 02, 2005 1:30 PMSubject: [AVR-Chat] Bootup/reset very big problem
Folks, i have a really bit problem i cant understand.
I am using ATMEGA32L on a 7805 powered board but i cant make it run
or even reset. The chip is proprerly powered , i tried a lot of reset
circuits, of course including the one provided by atmel, but there is
no way it runs by itself. The thing comes when a tie an external
voltage source to the reset pin (ex. an ISP programmer). Everything
seems to work fine, even the reset circuitry, but as soon as i take
out this external reset source, the chip halts. I dont have a clue
about what this could be. I am using internal clock source and tried
1 and 8 MHZ.
Ever happenned to you?? Suggestions??? ANY CLUEEEE!??????
Thanks
Javier