Hi All,
I have two Arduino Leonardo an both started to act the same for some reason. I can only upload a sketch to arduino if I press reset while Uploading stage.
Serial Port is grayed out all the time so I can't open Serial Monitor and every time I press reset button the port appears for 5-6 seconds and then goes away.
Any ideas what is happening?
Something is wrong. It could be on the computer or on the Leonardo.
Other boards use a real reset when a sketch is uploaded, but the Leonardo has a different sequence. You create a real reset by pressing the reset button.
You could try to re-install the drivers for the usb-serial. Since two Leonardo boards have the same behaviour, it is most likely a driver problem on the computer. Open the Device Manage and look for the COM ports. Update the drivers by selecting the drivers in the Arduino folder.
I hope you use a new version of the Arduino IDE ?
You could also try to re-write the bootloader on the Arduino boards. You need a programmer for that.
Adding additional details:
I uninstalled 1.0.5 r2 and installed the BETA drivers. Arduino did work at start until I unplugged from USB and plugged back in. Then it started to act the same. All of that is happening on Windows 8.
While making this post, both arduino work now again, but still act a bit weird. I can see that when I upload the sketch port changes to COM5 and then listen afterwards on COM10.
Regarding Bootloader, I have PL2303 programmer, will that work?
BTW: Thanks Peter_n for hints. They gave me some ideas.
The PL2303 is a usb-to-ttl-serial converter. A programmer is something like the USBasp.
Changing the COM ports is normal. The Arduino Leonardo has an ingenious/freaky usb-interface. It can emulate keyboard and mouse and upload sketches and and be a serial port. All of that with a combination of hardware and software in the Leonardo.
As a result, the COM ports disappear and appear when uploading a sketch.