The Leonardo R3 Board Micro-USB compatible with Arduino is a micro-controller board base on the ATmega32u4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs); a 16 MHz crystal oscillator, a micro-USB connection, a power jack, an ICSP header, and a reset button.
It contains everything need to support the microcontroller; simply connect it to a computer with a USB cable or power it with an AC-to-DC adapter or battery to get started.
The Leonardo R3 Board differs from all preceding boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor.
This allows the Leonardo to appear to a connected computer as a mouse and keyboard; in addition to a virtual (CDC) serial / COM port. It also has other implications for the behavior of the board.
Leonardo R3 USB Serial Port has disappeared from IDE
The Arduino Leonardo stands apart from other Arduinos, like the Uno and Mega, as it lacks a built-in USB serial chip. One microcontroller is responsible for both the USB stack and your code. If you upload code without the USB stack, your PC won't recognize the Leonardo. In this case, you can press the reset button to display the serial port on your PC for 3-5 seconds. During this time, you can upload your code.
While Arduino Leonardo is connected to your computer, press its reset button. A COM for Arduino Leonardo appears under the Arduino IDE: Tools > Port: You should upload the code within a few seconds just after you press the reset button while the Leonardo COM is appearing.
The USB stack and your sketch both run on the same microcontroller in this board, which means there's a possibility that your sketch code could interfere with the USB functionality.
Luckily, the upload code (bootloader) resides in a separate memory section, so it remains unaffected by your sketch code's actions.
However, triggering the bootloader requires precise timing during the upload process. Ordinarily, a specific segment of your sketch code that recognizes a 1200 baud connection signals the microcontroller to reset and activate the bootloader. But in your present scenario, this mechanism won't function as expected. Therefore, you'll need to manually reset the board to initiate the bootloader.
Timing is crucial. Resetting the board too early might cause the bootloader to time out before the upload begins. The challenge arises from the fact that when you click the "Upload" button in the Arduino IDE, it first compiles your sketch prior to commencing the upload. Hence, you must wait until the compilation completes before resetting the board.
Follow these steps:
Go to the Arduino IDE's menus and select Sketch > Upload.
Monitor the console window at the bottom of the IDE until you see a message like this:
python
Sketch uses 444bytes (1%) of program storage space. Maximum is30720bytes. Global variables use 9bytes (0%) of dynamic memory, leaving 2039bytesfor local variables. Maximum is2048bytes.
Quickly press and release the reset button on the Arduino board immediately after the compilation message appears.
Your sketch should now upload successfully. If the issue persists even after a successful upload, it indicates that something within your sketch is interfering with the USB functionality. You can verify this by creating a new sketch via File > New. If the board is then recognized by your computer and you can upload normally, the issue is indeed in your original sketch. In that case, you'll need to identify and rectify the part of your sketch that's causing the USB disruption.Featured By RoboticsBD.
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