Crystals

Questions on other types of hardware and getting it talking to the ARM CPU
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basicchip
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Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
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Crystals

Post by basicchip »

>from the help line
>I have a prostart board.
>What is the frequency of operation with out the crystal?

The CPU is running at 48 MHz

>To retrofit a crystal what is the part number of the crystal? I need the board to reprobate at 50 Mhz.

The following DIgikey parts would work well XC955, XC1380, SER3424
Also add the 30 pF caps

>Will the sparkfun 3 volt dongle work?

It would be better to use the 5V version, as the 5V is used for generating the 3.3V power
The ones on ebay also work (with FTDI parts), most have a 5/3.3V jumper



basicchip
Posts: 1040
Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
Contact:

Re: Crystals

Post by basicchip »

>from help line
>do you have a routine to change the clock frequency or must one poke?

Control of the PLL has to be done writing to registers, and it varies from part to part. Most are configured to multiply the internal trimmed RC oscillator to near the max clock rate.

What specifically are you trying to do?

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