Arduino Pro micro with Leonardo Bootloader

Hello i bought one of these board Ardino pro micro with the Leonardo bootloader on it because i was working on a pc keyboard project of mine So i got it in the mail today and i connected it and it says Com3 (Arduino Leonardo) so i selected the board for Leonardo and i try to upload the sketch just the basic blink led sketch and it said done Uploading Build options changed, rebuilding all Sketch uses 4,788 bytes (16%) of program storage space. Maximum is 28,672 bytes. Global variables use 151 bytes (5%) of dynamic memory, leaving 2,409 bytes for local variables. Maximum is 2,560 bytes. So it looks all good but nothing happens so i put a external led and resistor to D8 and change sketch to match the digital pin uploaded the sketch and nothing happens. Can someone please help me out.

I also forgot this is a link to my board Click here.

I finally mange to get it up and running now thing is this board doesn't have a D13 on it and in the blank sketch i forgot to change the pinMode(13, OUTPUT); on it. Strangely there is no D13 but there is a D14 D15 and D16 also there is no ic2 pins on this one.

On ATmega32U4-based Arduinos, I2C is on digital pins 2 and 3. You can use pin 17 to blink the RX LED for a simple on-board check.


Thank you dmjlambert. This board is way different then what I'm use to hehe

Yes, those Leos are pretty weird. In a "normal" Arduino the USB-to-serial function does not reset along with the main processor, so if your sketch malfunctions (such as run out of memory) the Leo won't even auto-reset and accept a new sketch any more. You have to put on your propeller hat to work with these things....

Hello then how do you clear it out the memory for new sketch? This is getting stranger by the minute lol

I should have said RAM. What I mean is: if your sketch stops running for some reason, such as it malfunctions due to a memory (RAM) leak, the USB port will stop working. You would then have to press the reset button at the beginning of upload to get it to accept a corrected sketch.

But wait, you haven't seen strange yet!

Of course, it doesn't come with a reset button... :slight_smile: The guy who invented this particular Arduino didn't need a reset button because his sketches always work the first time. I kind of like that guy!

Anyway, put it on a breadboard and wire up a reset button if you need to. I have also just used another Arduino as an ISP programmer and burned a fresh bootloader on it if I need to. Hey, no ICSP header! Well you need to find which pins are the MOSI, MISO, and SCK and hook them up. Are you having fun yet? I'm just teasing. But it is a pretty funny board. Actually this is my favorite type of Arduino. I'm going to get a Beetle next, it's similar but smaller.

Dude that funny as heck thank you sounds like one of them Tv shamwow commercial. Buy just wait if you buy this you also get this hehe. Thanks that made my night LOL

Hello can someone tell me if the ATMEGA32U4-AU has he same keyboard emulator as the ATMEGA32u4-MU?

Yes, that's the same chip inside, just different plastic package. One has the pins sticking out the side and the spacing is further apart, and the other has pad underneath which are very close together. The Leonardo has one style and the Pro Micro has the other.

Thank you.

OP, how did you resolve the Bootloader issue?
I have a pro micro and m IDE show COM3 Leonardo... the sketch I'm trying to upload won't compile :frowning:

OP, how did you resolve the Bootloader issue?
I have a pro micro and m IDE show COM3 Leonardo... the sketch I'm trying to upload won't compile :frowning:

Won't compile is different from the OP's problem.

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