Resonator setting on 16F886

[Walbeek]

Hi there,

I have programmed a flowcode (V5) listing and send it into a SOIC version of the PIC with ICSP.
On the PCB is a 20MHz resonator (instead of a crystal with two capacitors)
When I program the PIC with Oscillator set to HS in the configuration screen, the PIC doesn't seem to run.
When I change the Osc setting to "Internal RC clockout", the PIC reacts on I/O.
Can you please tel me what is the proper setting for a resonator (Kyocera PBRC20.00HR 50Y000)

Rinie

[Kenrix2]

20Mhz is definitely High Speed (HS) setting. Microchip's AN869 might help you in your design. You may need RFext to help it start oscillating. I have used a number of 12mhz resonators with built-in caps but, they were through hole package and they started oscillating extremely fast without the resistor. With care, you can hand solder the resistor. Best of luck to you.

[Walbeek]

Hello Kenrix2,

AN869 is about "External Memory Interfacing Techniques for the PIC18F8XXX", cant find anything about resonators and crystals.
I will try a resistor (1Mohm), maybe that will do the job.
My PCB is SMD so it will give some trouble soldering it on i think.
If you have any other aplication note suggestion, please let me know.

Rinie

[Kenrix2]

My error, sorry. The correct document is AN849. The last sentence on page five does recommend the R value you have chosen.

[Walbeek]

Hi again,

I have added the resistor, however no result.
Earlier it seems to have started once, but just only once.
For now, there is no result anymore.
Just a simple flowchart that checks 2 inputs and set two outputs.
Doe anybody have any suggestions on what to check?
Please let me know.

Rinie

[temtem]

maybe you have to check the MCLR pin, must be high (5volts or Vcc).

[dazz]

hi walbeek

cany you try the config settings below and see if it helps also can you attach your flowchart if it doesnt work
Regards
Dazz

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