i have been trying to work out why my Diecimila clone wont start up.. there are no bridges and the usb to serial section works fine.
I tested it by wiring it up to the Boarduino using the serial, reset, +5, and gnd. it uploaded sketches perfectly.. there was no chip in the Diecimila naturally.
but when i have a chip in (i got a new working atmega with blink on it) nothing happens.. i'm thinking when the old ship went down it took the crystal with it
Seeing as i have no replacement to test this theory what can i use in its place?. i assume it has to be 16 mhz so 4 wont work (i got 2 4 mhz oscillators in my harvest box, but they are 3 pin like the usb one and the one on the Boarduino).
Can a 555 timer be used in any way to emulate it? if so how? i just need to know if it is the crystal or not and i cant think of any other way of testing it to be sure.
I think you can change the Atmega fuses to work with internal clock, instead of external clock (crystal). It's less accurate, but I think this can prove if the problem is the crystal (or the caps connected to it, if they exist in your board).
i just need to know if it is the crystal or not and i cant think of any other way of testing it to be sure.
suggestions?
The crystal is basically a piece of rock with some wires attached to it. About the only way to damage it would be to mechanically disturb it. It's more likely that your fuses are wrong.
it broke after i repaired a bridge in the circuit when i discovered pin 6 (Digital) when used or a button was shorted to the ground somewhere.. it reset the board whenever used.
I removed the chip to make the repair.. the repair went flawlessly. the short was removed cleanly. but when i put the chip back on it wouldnt start..
i am wondering if the crystal may have had heat damage. as i had to try some resoldering on the chip bed (was in crooked but it was ok. more ugly than anything).
what shoud a mutlimeter show when testing the crystal cos i am getting a no reading on the continuity test (diode).
the crystal will read open circuit with an ohmmeter. I can pretty much guarantee you it's not the crystal- I have never seen a defective crystal. Check everything else, i.e. the traces, power at appropriate pins etc.
the crystal will read open circuit with an ohmmeter. I can pretty much guarantee you it's not the crystal- I have never seen a defective crystal. Check everything else, i.e. the traces, power at appropriate pins etc.
D
yup i discovered that one myself earlier crystals don't register :)..
i may have one or 2 caps out then i suppose. I'll do more tests on the ones i suspect and get back to u. hopefully i have replacements if its them..
but i dont actually know how to change the fuses :S
crystals don't register :)..