Will the propeller work with a resonator?
CJ
Posts: 470
like the 20Mhz one on the OEM BS2, or are crystals the only way to go?
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
Comments
I believe the specifications are from 4Mhz to 8 Mhz. The Propeller boosts it to a high rate with a multiplier, a PLL device
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 4/5/2006 4:34:24 AM GMT
I'd like to correct what Kramer stated....
Sure it can..... all the way up to (currently) 80 MHz. In such a case the PLL multiplier is configured to be disabled. With the PLL I was able to get mine up to about 95Mhz.
When the Propeller boots, first it runs on its internal RC oscillator, and then once it loads the Spin interpreter into Cog0, your program sets the oscillator configuration details, and away it goes.
Furthermore, I believe that future incarnations of the silicon will in fact run at higher speeds (native, and pll mode to 128 Mhz) as well as draw less power.
Cheers,
Peter (pjv)
http://forums.parallax.com/forums/default.aspx?f=25&m=118452
that the pll could be set to 1x, 2x, 4x, 8x, or 16x.
I was primarily wondering if it would be compatible.
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
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Jon Williams
Applications Engineer, Parallax
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Who says you have to have knowledge to use it?
I've killed a fly with my bare mind.
I might be wrong about this, but I think that when the PLL is enabled, it always operates at 16x, and the taps select frequencies that are divided down from that. The range of xtals for use with the PLL is limited to 4--8mhz, so the 16x PLL can operate between 64 and 128mhz. It would not be possible to use the PLL with a 20mhz xtal. It would be possible to use a 20mhz or 50mhz xtal directly, though, without the PLL enabled.
With the prototype chips, the recommended maximum with the PLL was 80mhz, a 5mhz xtal or resonator.
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Tracy Allen
www.emesystems.com
Alternatively, is there a significant EMI advantage to using one or the other?
I had just presumed that the 4-8Mhz had some advantage other than it is easier to buy crystals and resonators in that range.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Altough I have not yet tested this, I expect that the X16PLL approach off a 5 MHz crystal will be a little quieter, but that is yet to be confirmed.
Probably some time after a lot of other issues are investigated.
Cheers,
Peter (pjv)
Maybe I just inferred it from past threads on EMI at high clock rates.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Thanks again,
Brian
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Chip Gracey
Parallax, Inc.
From my understanding, some Murata resonators ALSO have built-in caps. [noparse][[/noparse]The 3-lead version]
I suppose if they work, okay; but it would be best to keep it simple.
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"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)
······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
Post Edited (Kramer) : 4/16/2006 11:40:34 AM GMT