[SOLVED] Mini pro uploading problem

about one year ago, using IDE 1.8.1 I created a project for mini pro 328 5V/16M. I wanted the minimun start time after apply power (no bootloader), so I modified boards.txt (FROM low FF, high DA, extended 05, TO EF, DA, FD). After testing the project on a nano I uploaded on promini, and restored original settings. Enerything fine.
Last week I had another project for minipro but no “fast” startup needed. So, after testing on nano I uploaded to minipro. But, although upload ended correctly, this was not ok!
a. minipro had a “fast” startup.
b. wathdog (wdt) was not working.

Same happened on second try, on another minipro.

I downloaded 1.8.1 on a separate folder and compared boards.txt files. No difference on mini pro settings.

(Version 1.8.5 doesn’t have a boards.txt file so I didnt try)

Any ideas?

On my system with IDE 1.8.5: C:\Program Files (x86)\Arduino\hardware\arduino\avr\boards.txt

How do you program the board? Using ICSP?

The boards.txt you find in the Arduino IDE installation folder will not be used by the Arduino IDE if you have installed a different version of Arduino AVR Boards via Boards Manager. Arduino AVR Boards 1.6.21 was recently released, which caused people to get update notifications so there's a good chance you did install a new version.

The easiest way to find the active hardware package location is as follows:

  • Select a board from the hardware package from the Tools > Board menu
  • File > Examples > SPI > BarometricPressureSensor
  • Sketch > Show Sketch Folder
  • Move up folder levels until you reach the one that contains boards.txt

b. wathdog (wdt) was not working.

The Pro Mini bootloader has a bug that causes it to go into an endless reset loop after a watchdog reset. Is that what you mean by "not working"?

The Pro Mini bootloader has a bug that causes it to go into an endless reset loop after a watchdog reset. Is that what you mean by "not working"?

The actual scetch is using Serial ie, If there is no reception (4sec) wdt is activated. So I expect to see an extra led on D5 (showing restart of sketch) to blink for three times. When I press and release the reset button, the led never lights up, instead the only led on board lights up immediately and blinking.
Perhaps you are right, it is a loop.

Since you say there is a "wdt issue on mini pro" and I dont have time to redesign I simply change immediately to nano (the few milliamps more consumption is not citical). Only the more length of nano will force a 90degree rotation of a 4pin small power supply module.

Thank you

The old Nano bootloader has the exact same bug. Arduino just started putting the excellent Optiboot bootloader on their Nanos, which does not have the bug. But there are likely still a lot of Nanos out there with the old bootloader so it's uncertain which one you would get if you bought a Nano. I think it's very likely to get the old bootloader with clones or counterfeits since they probably haven't even noticed the change yet.

If you have an ISP programmer or an extra Arduino you can use as an "Arduino as ISP" programmer, you can simply do this:

  • Tools > Board > Arduino/Genuino Uno
  • Tools > Burn Bootloader

That will install the Optiboot bootloader on your Pro Mini. You will no longer be subject to the watchdog reset loop bug and it will also free up 1.5 kB of program memory. In fact you will be better off doing that than buying a new official Nano since they screwed up and left the bootloader section set to 2 kB even though Optiboot only needs 0.5 kB so you won't gain the extra program memory with the official Nano.

I forgot to say that after you burn the bootloader to your Pro Mini with the Uno board selected you need to always use it with Uno selected in the Tools > Board menu from there on.

The old Nano bootloader has the exact same bug.

yes, you are right. it seems that the nano I was working on prototype was with optiboot.
But, although i "burn" the bootloader (using an arduino as ISP under IDE 1.8.1) and burning seems to "complete succesfully" behavior is exactly the same. that is, when power on, sketch starts ok but when wdt is activated after 4 sec (wdt 4 sec) nano falls in loop before "setup".


its working!!!
thank you ALL