Matrix user forums

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

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.

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

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

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

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

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