Crystal configuration question.

[E*2Engineer]

Hello all,
I just got done troubleshooting a programming a problem through trial and error, a method which is time consuming and frustrating.

My system with Flowcode 4 or 6 would not program, or at least run the pics I tried to program if the setting was XT. HS solved the issue it turned out.
So I am curious, what is difference in the code/ hardware that made one work and not the other? When should XT be used?
Thanks,
Craig C

[kersing]

Have you considered checking the data sheet of the controller you're using?

Simply entering "microchip xt hs" in Google results in a link (second result) to the Microchip website with this document explaining the different modes. From that document:

The main difference between the LP, XT, and HS modes is the gain of the internal inverter of the
oscillator circuit which allows the different frequency ranges

The data sheet of your specific controller will specify the frequency ranges for the different settings. If you look at the data sheet for the 16F877a, page 146 specifies the capacitors and mode to use for different crystals, with XT for 200kHz-4MHz and HS for 4MHz-20MHz.

[E*2Engineer]

To answer your question, quite frankly no, I actually forgot to check the datasheet for that.
I am on painkillers, pre knee surgery and have been having a tough time thinking clearly.
But thanks for the information anyway. It does answer my question, so 1 credit for you in the "thanks" field.
Thank you
-Craig C

[kersing]

Hi Craig,

No problem, I'm only trying to point people (like you) to a quick source of answers. The forum relies on someone reading and answering the question which can be a wait. Data sheets are available around the clock.

Best regards,

Jac