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Qt Py with external crystal
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Qt Py with external crystal

by mre2007 on Sat Apr 10, 2021 1:36 pm

Hi! I would like to play with adding an external crystal to my Qt Py. I would like to know if I need a SWD programmer to ultimately build this feature in or whether there might be a compiler flag or env variable that I can use with a standard build using Arduino IDE. I have the same crystal as used on the Arduino Zero connected to A0 and A1.

Thanks!

mre2007
 
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Re: Qt Py with external crystal

by mikeysklar on Sun Apr 11, 2021 9:48 pm

Looking at some other discussions of SAMD21 crystal setups it seems like they were able to follow the spec sheet for the processor and direct connect an appropriate sized crystal 32kHz / 12.5pF without getting into bootloader issues. What are the specs of the crystal you have? Take a look at this thread.

https://forum.arduino.cc/index.php?topic=688566.0

mikeysklar
 
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Re: Qt Py with external crystal

by mre2007 on Sun Apr 11, 2021 9:57 pm

Yes I saw these. I wasn’t sure if the boot loader would look for a crystal and use it if it found it, or whether or not I needed to do something special. I went ahead and bought a SWD programmer - I was asking so I could avoid doing so if it wasn’t needed.

mre2007
 
Posts: 9
Joined: Tue Mar 23, 2021 10:24 pm

Please be positive and constructive with your questions and comments.