As with the little crystal problem i've had last few days, i finally found out why it didnt work but I dont understand it..
It happened that the crystal I used cannot be grounded in order to work. I can only make it work like the circuit in the attachment. Is it normal?
I'm using Nigel's main board and Led board for testing using PIC16f628
I attached the 2 legs from the crystal to RA6 & 7, and then my board turns on the LED on portb blinking at 1 second interval. But this is without any capacitor and grounding... (SPOOKY..) Does anybody knows why?
EDIT: it doesnt work already after i tried it again. would it because there's charge left inside the crystal? It's just plain wierd..
Connect the capacitors, they are an essential part of the oscillator circuit - without them it 'may' work some of the time, due to stray capacitance, but it's unlikely to be reliable.
Same thing happened me the other day .I was wondering what was wrong until I removed the caps. It's still working away now.
I don't have the part no. for the crystal to find out what the story was.
The shorterway from the Crystal to the cnotroller the bether. This way you get the most correct freq. as you can control the stray capacitance (witch is on all PCBs more or less).
There are some ways to control the stray capacitance as shown on the pic below (snapped from DS1302 Datasheet). For Crystals that are used with PICs the caps are used for stability and to keep the crystals BandWith very tight. (I mean to have read somewhere that its like 3-4 Hz)
I've finally found a way to make the crystal to work. After trying to abandon the 16f628 by using 16f84a, i noticed a statement from this spec, saying that it is recommended to use HS mode for crystal higher than 3.5mhz rather than XT mode. so this took me a week to finally solve.
I've finally found a way to make the crystal to work. After trying to abandon the 16f628 by using 16f84a, i noticed a statement from this spec, saying that it is recommended to use HS mode for crystal higher than 3.5mhz rather than XT mode. so this took me a week to finally solve.