What frequencies are "Usart friendly" quartz Crystals for for Xmega series?
I have read manual for Xmega, but didn't find this info.
Usart friendly quartz Crystals for XMega ....
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115200*16*n
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It depends upon what you refer to as being user friendly.
Pretty well any xtal will work. Probably the most critical is the frequency for baud generation at high baud rates. There are a few "sweet" frequencies that give zero error at high baud rates.
viz. 1.8432, 3.6864, 7.3728, 11.0592, 14.7456,18.4320 MHz
I would have thought that these would be in the data sheet under Examples of Baud Rate Setting. Perhaps you are only looking at the summary document.
mbruck wrote:
What frequencies are "Usart friendly" quartz Crystals for for Xmega series?I have read manual for Xmega, but didn't find this info.
Check out Application Note AVR1307: Using the XMEGA USART - there is a spreadsheet that calculates errors for various clock frequencies.
I use a 16M xtal and I can quite happily pump out pretty much any standard baud rate at under 0.1% error (IIRC).
-- Damien
Quote:
He didn't say "user friendly", he said "usart friendly".
It depends upon what you refer to as being user friendly.
The xmega is a special case as it has a sort of 'fractional divider' for its baud rate generator. The xmega will generate a more accurate baud clock than will the atmega at high rates.
Level: Raving Lunatic
Joined: Fri. May 4, 2007
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Location: Geelong Australia, Home of the "Cats"
usart vs user :oops:
Must go and see the optometrist! :)
OK on the xmega baudrate generator flexibility, very nice!
I can get my usart working from internal rc Oscillator. Even you can use 115200 without the need of an external crystal!!!Cause this is xmega land...!