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jabidof
Joined: 25 Jul 2003
Posts: 80
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 14 Apr 2008 16:44 recommended capacitance 40mhz |
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Hello there,
I can't find the capacitance value to use for a PIC18F MCU clocked at 40MHz.
I see that from 1MHz up to 25MHz Microchip is proposing 15pF. But no mention for 40MHz.
Anyone can help?
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rkodaira
Joined: 08 Jun 2004
Posts: 332
Helped: 54
Location: Sao Paulo - Brasil
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14 Apr 2008 17:40 pic18f1320 crystal selection |
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| Usually the 40MHz clock for 18F series PIC comes from a 10MHz crystal and activating the internal PLL that multiplies the 10MHz by 4. Check the datasheet to be sure.
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s_brune
Joined: 28 Feb 2008
Posts: 8
Helped: 1
Location: USA, MI
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funnynypd
Joined: 09 May 2007
Posts: 919
Helped: 21
Location: USA & Canada
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15 Apr 2008 0:00 Re: PIC18F series quartz 40 MHz capacitance value |
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| jabidof wrote: |
Hello there,
I can't find the capacitance value to use for a PIC18F MCU clocked at 40MHz.
I see that from 1MHz up to 25MHz Microchip is proposing 15pF. But no mention for 40MHz.
Anyone can help? |
The maximum crystal you can use is 25M Hz. 40 Mhz is not recommended, you can use 10M hz and 4x PLL though.
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15 Apr 2008 0:00 Ads |
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Scotty
Joined: 26 Nov 2006
Posts: 4
Location: Finland
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16 Apr 2008 9:14 Re: PIC18F series quartz 40 MHz capacitance value |
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| Yes, and correct capacitance would be commonly used 22 pF.
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