Most of the tutorials for using an Uno as an FTDI tell you to remove the Atmega328 from the Uno board.
A couple places I've read, that if you don't remove the chip, it will be programmed the same as the Pro Mini.
It seems to me that it is easier to reprogram the Uno again, rather than risk breaking my Atmega328 during removal / re-install.
Can I leave my chip in my Uno when I program my new Pro-Mini?
Thanks in Advance!
You should be able to leave the chip in, and tie RESET to GND. This will keep the 328 in RESET state, where it won't listen to (or drive) the serial signals.
lil_satan:
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It seems to me that it is easier to reprogram the Uno again, rather than risk breaking my Atmega328 during removal / re-install.
Opinion: If you want easy, invest in an FTDI module or cable. This is just one of those little things that is as necessary as a DVM for the entry-level workbench.
All that mucking around with jumpers from the UNO to the mini is just fine until the day when you smoke something on the UNO or Mini Pro... then the replacement cost will exceed the FTDI.
Ray
Wow! Same - unusual - query twice on the same day, or within a day. 
OK, let's see if we can get this sorted.
There are two ICSP headers on the UNO (R3) board, one for the 16U2 USB to TTL converter, and one for the mega328. By placing a jumper between pins 5 and 6 on the latter one, you disable the mega328 in which case all its I/O pins are open and you can connect your Pro Mini TX and Rx to pins 0 and 1 to communicate with the USB to TTL converter. There is no interaction between reset on the mega328 and reset on the 16U2.
So why would there be a suggestion to remove the chip?
Well,
If you remove the chip, you can connect the reset pin (not "GRN") on the Pro Mini to RESET on the UNO and the auto-reset will work perfectly well. Clearly if you have instead grounded RESET on the UNO in order to disable the MCU, you cannot do this and will have to manually reset the Pro Mini using its own reset button, pressing it momentarily when you see the "Done Compiling." message in the aqua (coloured) bar below the code window in the IDE.
mrburnette: My FTDI cable is on it's way.. I need something to do when I can't sleep.
Paul__B: I went ahead and removed my 328 and it's working great, with a manual reset.
That said, I'm sweating bullets thinking that I'm going to have a clumsy moment and knock my 328 off it's little safe spot in my shop.
You're saying I can put a jumper on my uno, and I'm good? As long as I do a manual reset?
Where do I put this jumper?
lil_satan:
Where do I put this jumper?
Paul__B:
There are two ICSP headers on the UNO (R3) board, one for the 16U2 USB to TTL converter, and one for the mega328. By placing a jumper between pins 5 and 6 on the latter one, you disable the mega328 in which case all its I/O pins are open and you can connect your Pro Mini TX and Rx to pins 0 and 1 to communicate with the USB to TTL converter.
You're saying I can put a jumper on my uno, and I'm good? As long as I do a manual reset?
Where do I put this jumper?
Connect Reset to Gnd on the Power header - same effect as pushing & holding the Reset button.
Will not damage anything.
Sooo...
Just to be clear...
I can't open that.
Save the picture locally, then click Reply and use Additional Options to Browse to the picture and Attach it.
Ok, I got it now! And the auto reset is working! Thats a relief!
Thanks a million!
And this is how to wire it with the chip still in, and jumper on ICSP pins 5,6. With reset wire functioning...
In #11, Reset is connected to GND on the Promini.
In #12, Reset is not connected.
I think your descriptions are a little mixed up.
In #11, Reset must be connected to the terminal labelled "GRN" on the Pro Mini.
#12 is correct - with the Reset jumpered on the UNO, you have to use the reset button on the Pro Mini.
Note that the "FTDI" terminals on most "clone" Pro Minis as well as the original "Mini" run in the opposite direction to that shown which is for the original Pro Mini.
