Helpful ReplyHot!External Oscillator PIC32MZ

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Cosme_Fulanito
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2017/07/18 20:14:49 (permalink)
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External Oscillator PIC32MZ

Hello everyone,
 
I'm working on a board with the PIC32MZ1024EFG064. I'm having issues with the external oscillator. I'm using a 8Y-16.000MAAV-T crystal. The board is rather small and trying different things is quite a pain. The circuit is not oscillating.
 
If I disconnect the crystal and the capacitors I have around 500mV on OSCO and no signal on OSCI. Is this normal? I've tested other boards and I had voltage on both pins.
 
When I connect the crystal and capacitors I get different results, influenced I think by my scope probes. The best I get is a signal at the correct frequency on OSCI but it's only 600mV pk-pk.
 
I'm a bit lost. The board looks okey, I can't find anything wrong with it. Any ideas?
 
Thank you
 
 
post edited by Cosme_Fulanito - 2017/07/18 22:24:40
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qhb
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Re: External Oscillator PIC32MX 2017/07/18 21:06:37 (permalink)
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Cosme_Fulanito
Hello everyone,
 
I'm working on a board with the PIC32MX1024EFG064. 


No such device, do you mean PIC32MZ1024EFG064 ?
 
According to the errata for that PIC, the oscillator circuit is buggy.
http://ww1.microchip.com/...eviceDoc/80000663D.pdf
 
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Cosme_Fulanito
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Re: External Oscillator PIC32MX 2017/07/18 22:25:49 (permalink)
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I do mean MZ, I updated the post. 
 
Revision A1 Silicon: A crystal oscillator cannot be used as an input to the Primary Oscillator (POSC) pins OSC1 and OSC2
 
I can't believe this.
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simong123
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Re: External Oscillator PIC32MX 2017/07/19 04:18:22 (permalink) ☄ Helpfulby Cosme_Fulanito 2017/08/30 20:32:39
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It always pays to read the errata, especially for new parts.
 
The A1 parts are now mostly out of the channel. You can use a 24MHz crystal without modifying the standard cct with A3 parts. Personally I usually use oscillators (not crystals), as I find them to be more reliable and less affected by environmental factors.
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Cosme_Fulanito
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Re: External Oscillator PIC32MX 2017/07/19 07:38:24 (permalink)
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Lesson learned on reading the errata sheet.

How can I identify the revisión on the supplier? I think I got these from Digikey and they were A1.
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RISC
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Re: External Oscillator PIC32MX 2017/07/19 13:20:45 (permalink) ☄ Helpfulby Cosme_Fulanito 2017/08/30 20:32:25
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Hi,
There is no way to identify silicon revision from the references on the package unless you contact Microchip technical support .
I guess that after a certain datecode on the package maybe you can ensure it is A3 by contacting tehcnical support
When you connect your board to the debugger it will tell you what the silicon revision is as it can be read from internal registers.
A1 silicon works with an external oscillator (TCXO).
A3 works with several XTAL values (follow the erratasheet recommendation) Rs resistor is needed
Regards
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jcandle
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Re: External Oscillator PIC32MX 2017/10/09 18:11:07 (permalink)
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Omfg i missed this... need to check my revision and mayde buy oscillators...
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jcandle
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Re: External Oscillator PIC32MX 2017/10/12 14:35:10 (permalink)
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Arrow inventory was still A1.  I get to deadbug oscillators...
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