Nystax:
I'm using Arduino Uno to upload sketches to Arduino Pro Mini 3.3v clone:
Hi Nystax,
Can you upload the same Blink sketch twice in a row? Do the other sketches you upload enable the watchdog timer? Have you confirmed that your FTDI adapter successfully resets the pro mini when trying to upload?
Once the bootloader is installed I have never had any issue uploading sketches, except when getting into an infinite watchdog reset loop. Even then I can upload by beating the watchdog timer.
For burning the booloader I found I had to convert the 5V logic levels to 3.3V to get reliable results; but that hasn't been an issue with the FTDI adapter.
Sounds like the DTR pin of your serial adapter is not connected to the appropriate pin on the pro mini, hence it is not being properly autoreset, and the bootloader isn't running when you';re trying to upload.
I cannot upload any of the sketches twice in a row. Looks like uploading anything messes my bootloader. I'm using Arduino as ISP to burn bootloader and AVRISP mkII to upload sketch. I don't have any other programmer to test other solutions right now.
My connection is like this:
If you're using an Uno with the chip removed as a serial adapter, reset goes to reset (and this may not work reliably); the pin on the end of the board that you have it connected to needs to be connected to the DTR pin of the serial adapter, which is not broken out on the Uno (since it's not meant to be used as a serial adapter).
I strongly advise you to go buy a serial adapter - they;re like $2 shipped, what's stopping you?!
Unfortunately unremovable chip.
I guess nothing stops me now, it's just first time I think I will need it and have to buy it online, hard to come by in the area.
Yeah - using Arduino as a serial adapter is not a winning strategy. TBH, neither is using one as an ISP adapter, you can get USBAsps for like $3; unfortunately the f/w they come preloaded with is buggy and the update process is annoying. And Arduino as ISP is usable if you're able to connect the wires right consistently (we have a lot of people on these forums for which this seems to be a challenge)
These are the ones I use (no endorsement of that particular vendor, but I do endorse that model - the ones with the voltage switch and the button - I've tried a few models of cheapo serial adapters, and these are the best. They actually work when set for 3.3v; some of the ones where you're supposed to cut and jump on the back to switch it to 3.3v don't work if you do). There are a few vendors that only advertise 5 at a time (the cheap sellers!); they actually restock within minutes if you buy them out - it's irritating when you're trying to buy 20 of them!
Watch out for the adapters where they show a jumper in place on the 6-pin connector - those do NOT break out the DTR pin and are not useful to us.