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Jun 27, 2017 at 5:18 comment added Jot @Cerin, remove the modemmanager.
Jun 27, 2017 at 2:52 review Close votes
Jun 28, 2017 at 8:12
Jun 27, 2017 at 2:27 comment added Chris Stratton @Cerin - Actually Arduino documentation is notoriously, and universally, horrible in comparison to that of actual engineering components, libraries, and APIs. In any other context, the fact that a USB stack can be broken by uncareful use of interrupt disables, clock, or I/O setting changes, or general memory corruption or execution runaway is well known.
Jun 27, 2017 at 1:31 comment added Cerin @Jot, These problems began when I flashed the most recent bootloader using the 1.8.2 IDE. That completely disabled sketch uploading via USB. I had to manually use avrdude to flash the bootloader, as I described here, to restore it. What problems does modemmanager cause? I have the modemmanager package installed, but it's a service that's not running.
Jun 27, 2017 at 1:25 comment added Cerin @ChrisStratton, Why is documentation of these shortcomings in the Leonardo so difficult to come by? Where's the list of things not to do so you don't disable your Leonardo? The Arduino community prides itself on documentation, but I found few solutions Googling this problem. Had I known it was so fragile and incompatible with Uno sketches, I would never have bought it. And therein lies the reason why these flaws aren't advertised...
Jun 26, 2017 at 20:29 comment added Chris Stratton A flawed sketch will not prevent reprogramming of an Uno; the same code on a Leonardo will prevent the logic that can intercept programming requests after the start of a user program from doing so. But it's still a badly written sketch.
Jun 26, 2017 at 19:29 comment added Jot @Cerin, I hear you. In linux, with an old Leonardo bootloader or third party bootloader, and a wrong sketch, and something called 'modemmanager' in linux, it is a real problem. In Windows and with a recent bootloader, it is working 100% okay. Do you have a programmer, and did you burn the bootloader with the Arduino IDE ? In linux, remove the 'modemmanager'. Yes, the sketch can be a problem when sending too much to the usb serial port. It could block something, preventing a restart of the bootloader.
Jun 26, 2017 at 18:36 comment added Cerin @ChrisStratton, I doubt it's the problem with the sketch. I was able to upload the same sketch to an Uno and didn't experience any issues. I heavily researched ways reset the Leonardo, and the near universal answer was that were was no reliable method, short of using an ISP to reflash the bootloader, which is what I did, and why I dislike the Leonardo. I expected this question to get heavily downvoted, because I know you're very defensive of these terrible boards, but I'll leave it up because I stand by my experience. Please everyone, avoid the Leonardo like the plague. It's a bad product.
Jun 26, 2017 at 18:30 vote accept Cerin
Jun 26, 2017 at 17:46 comment added Chris Stratton Your problems are likely caused by loading bad sketches. A more productive question would focus on the means of recovering from this, ie, identifying a reliable way reset the board and stay in the bootloader to erase the bad sketch.
Jun 26, 2017 at 16:16 comment added gre_gor Most of your question is just a rant. And your definition of a "real" serial port seem to be no native USB support. There are Arduinos with native USB support that are not 32u4 based but ARM based.
Jun 26, 2017 at 16:01 comment added Majenko Strange, I (and many others) have never had such problems with the Leonardo not the other 32U4 based boards.
Jun 26, 2017 at 15:37 answer added Michel Keijzers timeline score: 5
Jun 26, 2017 at 15:31 comment added Ignacio Vazquez-Abrams No Arduinos since the Arduino Serial have a real serial port. They all leave it to the USB-UART bridge (if any) to handle anything beyond RX and TX.
Jun 26, 2017 at 15:25 history asked Cerin CC BY-SA 3.0