3pin resonator

asjad · Posted: Sun May 23, 2004 12:55 pm

Dear all,

I have recently bought a 3pin ceramic resonator (built in capacitors)

Can I assume that the outer 2 pins are for the PIC and the centre for ground.

Any sugestions
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I need help it seems that when I program the PIC16F874 and press reset it takes about 10seconds for the program to start and even then it works slower than I expect it too, all coding is correct.

Could it be incorrect connection of the 3pin resonator???
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Best Regards

davidpk · Joined: 29 Apr 2004 Posts: 13 Location: Opelika, AL

A manufacturer and part number for your part would help. (The resonator, not the PIC Wink

)

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

Typically the outer two pins connect to the xtal1 and xtal2 pins of the PIC and the center pin is ground.

If you can find a datasheet for the part, check the capacitance values, they may not be high enough or they may be too high. Also if the ground pin is unconnected or poorly connected (high impedance) it could exhibit the problems you describe.

Also set your fuses correctly, XT for up to 4MHz and HS for higher speeds.

I also like to use the Power Up Timer fuse on all my projects.
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Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

asjad · Posted: Sun May 23, 2004 2:08 pm

There is a very wiered symbol on the resonator , I am unable to find the manufacturer, the link below is the type I have

http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=30427&STK_PROD_CODE=M29222&XPAGENO=1

CAN ANYONE TELL ME THE MANUFACTURER OF THIS RESONATOR AND
PINOUT???
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Best Regards

Gabriel Caffese · Joined: 09 Oct 2003 Posts: 39 Location: LA PLATA, ARGENTINA

One of major 2 or 3 pin resonator manufacturer is MURATA.
They are usually blue, so, they don´t seem to be MURATA.

Apart from this, aren´t you paying too much for a resonator ?
The prices I see in this page are nearly same price as cristals -wich are far more accurate-

Gabriel.-

davidpk · Joined: 29 Apr 2004 Posts: 13 Location: Opelika, AL

All of the data sheets I've just browsed for these parts show the connections exactly as you have done. None of the data indicate that this would work, but I would try it in a pinch, swap the OSC1 and OSC2 pins. It shouldn't make a difference but there's always things not shown on data sheets that the manufacturer assumes.

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

dyeatman · Joined: 06 Sep 2003 Posts: 1934 Location: Norman, OK

Yes, it appears they are the ECS resonators (i have a bunch of them stored away, I use can oscillators now) with the same markings and yes the two outside pins are the XTAL inputs with the center ground.

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

asjad -

Is this related to the lcd & rtc code you are posting about?

I mentioned in that post to use an oscilloscope and x10 probe to check that the oscillator is running and also to watch an output pin toggle once each interrupt (modify your interrupt code of course).
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!