Programming arduino pro mini via arduino Uno


Was trying to follow an instructable at to program my pro mini using my Uno, but keep getting a avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x9a type of error. Quite sure I connected everything properly, and the yellow light on the mini does flash quickly a couple of times during upload start before settling back into a blinking yellow.

Has anyone had success programming the pro mini with the uno? Thanks for reading.


You linked a blog post, not a page on instructables, and it says nothing about programming a pro mini using an Uno. They program it using a standard USB serial adapter. Also, you don't normally need to use another arduino to program a pro mini, only to fix the bootloader. Otherwise, you can use any USB-Serial adapter that breaks out DTR.

Did you mean to link a different page? If not, we have no clue what you're asking, so please clarify :-)

I think it's a perfectly great idea to use another Arduino as a serial adapter for programming. It's usually easier to use it for ISP programming, as that's the more common usage. You could disable the automatic reset on the Uno, then have it use a dedicated line to reset the Mini. Then it's just a matter of passing through all USB data to a SoftwareSerial connected to the Mini.

Wrong link, replaced.
I don’t have an adapter but I have an Uno. I’ll have to wait over a week for the adapter to get here, hence trying to make do.

I read something about using another arduino to reset the mini, but in this case I don’t have the USB serial adapter so I’d like to use the Uno for the whole procedure. If possible of course.

OK, I looked at the instructable. I would not do it that way: you are going to damage the pins on your 328P if you put it in and out of the socket more than 2 times.

Look up 'Arduino as ISP". That's a better way to do it, although it doesn't use the programming header of the Pro Mini, which may be a problem if you've already put it into a project.

I think I see what happened. I read the instructable rather than watching the video, and didn't notice that the chip gets taken out, so I didn't do that.

From what I've heard before Arduino as ISP is used to burn a bootloader to another chip. Can it also be used to program the board? If so, is there a good guide for that?

I don't want to damage the IC, but would it be fine to take it out once? I have a spare Uno and can let it sit without the 328 for a bit while I'm figuring out the pro mini.

Arduino as ISP can be used for programming via ICSP generally not only burning the bootloader. The guide here on website is focused to burning the bootloader to another board or chip and it works without problems.

While I successfully uploaded the ISP sketch to an Uno board, I can't find how to target specifically a pro mini board with this method (i.e. which pins to choose). I tried to use the ICSP headers on both boards and conect those directly, then select Arduino as ISP as the programmer in the IDE, and tried to load a sketch, but got a not in sync timeout error. Not sure which pins to connect to which otherwise. Does anyone have a connection scheme for the Arduino Uno ISP to a pro mini? Otherwise I'm stuck waiting for the adapter to get here or using the method with removing the Uno's chip.


Probably long overdue, but incase someone else stumbles here programming the Pro Mini using an UNO, or using the Instructables link...

The key to making it work, is when you hit "upload" press the reset button on the Pro Mini.

Some misinformation posted here - you don't need to remove chip on Uno board, just understand, that you'll program the Uno simultaneously, like that's a big deal.

Of course there are better ways, but who wants to waste time buying another cord - especially if you got an Uno lying around - and if you've got a Pro, you probably have an Uno.

Finally, the wire layout on Instructables works just fine - again, remember the reset button on the Pro.

I don't mind the beating's and berating here on the site, but the original question was quite simple.

Or just connect Reset on the Uno to Gnd. Leaves the 16U2 free to act as USB/Serial for the Promini while the Uno's processor just sits there inactive.

CrossRoads: Or just connect Reset on the Uno to Gnd. Leaves the 16U2 free to act as USB/Serial for the Promini while the Uno's processor just sits there inactive.

Let me get this right. You connect "reset on the Uno to Gnd" on the Uno, correct?

Yes. Look at the Uno Power header - connect Reset to the Gnd.