| ??? 01/27/10 03:25 Read: times |
#172749 - so ... Erik ... what's your point? Responding to: ???'s previous message |
Erik Malund said:
The ATMEL pirece oscillators work as well as anyone's, but those don't work well at the 3rd harmonic. Few of them work well at frequencies much above 20 MHz and, AFAIK, none at all at 3rd overtone. as Kai (an Atmel fan, if I recall) stated some of the (newer?) Atmel chips do not work well at higher frequencies even with a fundamental crystal
There is (as far as I know) no '51 derivative, Atmel or not, that oscillates at the overtone with an overtone crystal. ... and that's exactly why one might want to try a crystal oscillator. Anyhow, in these EMI concerned days I much prefer to work with a PLL equipped derivative if a higher frequency is required.
Erik PS as seen in http://www.8052.com/forum/read/172729 I am definitely not trying to start a food fight. I doubt that EMI is a large concern for the O/P who's simply experimenting with his first 805x. A crystal oscillator will verify the oscillator/performance ratio that he was trying to verify. A crystal oscillator will always work, irrespective of who manufactured the MCU. As Kai has pointed out in past writings, the crystal oscillator circuit built into the MCU doesn't always behave as expected, particularly when the capacitors aren't properly sized. Further, I seriously doubt that the O/P is at all interested, at least at this stage, in what preferences you might have. He's clearly stated what he wanted to do, and you, Erik, haven't suggested anything that might help. RE |
