Uno will not upload at 115200 Baud

I bought a new Uno yesterday, and it would not accept an upload. I tried it on both Windows 7 x64 SP1 and Windows XP sp3 using Arduino-1.0.1 . I have an older Duemilanova, which I was able to upload on XP and Win 7. After uploading on the Duemilanova, I switched the cable back to the Uno but forgot to change the board back to Uno. It then uploaded! After looking into the differences, I saw that the boards.txt file showed the Duemilanova at 57600 and the Uno at 115200. I changed the Uno to 57600 and it uploads fine now.

Is my Uno defective? Should I return it to the store?

Here's the error messages I get at the higher speed:
Binary sketch size: 1,084 bytes (of a 32,256 byte maximum)
F:\arduino-1.0.1\hardware/tools/avr/bin/avrdude -CF:\arduino-1.0.1\hardware/tools/avr/etc/avrdude.conf -v -v -v -v -patmega328p -carduino -P\.\COM3 -b115200 -D -Uflash:w:F:\DOCUME~1\BILL-A~1\LOCALS~1\Temp\build6680546053503915563.tmp\Blink500.cpp.hex:i

avrdude: Version 5.11, compiled on Sep 2 2011 at 19:38:36
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2009 Joerg Wunsch

System wide configuration file is "F:\arduino-1.0.1\hardware/tools/avr/etc/avrdude.conf"

Using Port : \.\COM3
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Send: 0 [30] [20]
avrdude: Recv:
avrdude: stk500_getsync(): not in sync: resp=0x00

avrdude done. Thank you.

No need to return - just put the proper bootloader on it, if you have an AVR ISP.

If not, you seem to have a workable solution.

That is strange. Sounds like it's not a 'true' Uno but rather a clone version that used the older bootloader, as I'm pretty sure the 'official' Uno board was released with the higher speed bootloader only. Can you determine what kind of USB serial converter chip it has on the board?

Anyway if you have access to either a hardware ICSP programmer or even another arduino board you can as CrossRoads said pretty easily said just burn the proper bootloader into the chip. Also you could buy a 328p chip that already has a Uno bootloader chip burned into it, several vendors offer that at around $6 + shipping or so.

Lefty

This is supposed to be a real Uno. I bought it at Radio Shack. The box says Arduino Uno. The board itself says Arduino Uno R3 and Made in Italy. The board has 2011-3-02 etched into it on the bottom under the dc connector. The CPU says 1205, so it must be a recent build.

So only the bootloader controls the upload data rate?

"So only the bootloader controls the upload data rate? "
boards.txt has the rate the PC is using, bootloader has the rate the uC is using, the two need to be in sync.

billth87:
This is supposed to be a real Uno. I bought it at Radio Shack. The box says Arduino Uno. The board itself says Arduino Uno R3 and Made in Italy. The board has 2011-3-02 etched into it on the bottom under the dc connector. The CPU says 1205, so it must be a recent build.

So only the bootloader controls the upload data rate?

That is very strange. Radio Shack does carry the 'real' Uno boards as a big deal was made when it was announced that RS would carry some of the Arduino line of products. So maybe you have a real 'collectors' item there, kind of like some of those mint coin errors that collectors love to find. :wink:

EDIT: Any chance there was a manufacture error and a 8 mhz ceramic resonator was installed by accident rather then the designed 16 Mhz resonator? You could probably write a simple sketch using a delay function to see if the board is running at half the speed it should be running at?

Lefty

The crystal says 16 MHz on it. I took blink.ino and changed the delay for the off state to 10,000. The off is now 10 seconds long. So the clock looks to be OK.