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Topic: Atmega 8u2 update with UNO R2 (Read 2404 times) previous topic - next topic


The tuto for upgrade the firmware is always based on R1 layout although vias and tracks have moved in R2.
The eagle schematics and layout are always in R1.

Could we have it updated ?

I buy, in june 2011, an official UNO R2  Atmega 8u2 twice the price of a duemillanove on Ebay.
When I verify his firmware I find  rev 000. Yet the firmware as been updated in rev 001 in december 2010.
Is it correct ?
I think no.

There is no clear information towards Linux users that connexion with /dev/ttyACM0 is impossible without update the firmware ?
Is it correct ?
I think no.


How do you check the firmware version of the 8u2?
Does it matter that it is not the latest version, if it is working ok?



See :


Sep 09, 2011, 09:35 am Last Edit: Sep 09, 2011, 09:36 am by Texy Reason: 1
OK thanks for the link with the update details.
What that page does not tell is why the updated is needed, ie what is fixed with the new firmware.
What are the fault symptoms running older v.000 firmware?
I would also like to know the purpose of fitting the 10k resistor on the reset enable line, and the effects of fitting it
(mine does not have the resistor fitted). I have yet to check the firmware version, but my brand new Uno, received in the post yesterday appears to 'basically' work - I have downloaded a modified blink sketch which is working as expected, and now problems were encountered with downloading, etc

FYI I have the PTH Uno version, but I,m not sure how to check if its R1 or R2, there's nothing printed on it to say so ???


how to check if it is R1 or R2, there's nothing printed on

On my board it is printed (above Italy map):
Board Model

Other difference (sorry for english  I am French) on the R2  8u2 IC is not parrallel to the AT328 IC but turn 90 degrees.

Other difference (on my board) the IC 5V regulator is in sot223 package instead of Dpack (thermal resistor jonction/case of 15d°/W instead of 6d°/W)-> this decrease the capability of power sharing with shields

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