Auto reset when plug in DUT

[gyboy]

hi, I have to say this tool is so useful,but I found some problems when using it, usually when the the dut was pluged in the deviceafter it had power on(especially comsumes heavy current), the device will auto reset while I can see the boot led is breath and then display the first page. I have confirmed that it was not made by the voltage dropped down, I doubted that mabye the usb data line influenced the mcu while I did not found any influence inthe code,I do not know how to solve it,can you give me some advice,ths.

[FriedCircuits]

Hi,
Sorry for the delay in getting back to you. I have seen this issue from time to time and never figured out what it was. Something is triggering the ATmega32u4 to enter the bootloader. I know that the way the bootloader is usually entered is to open the serial port at 1200 baud and then disconnect and reconnect to reprogram. I thought it would be due to voltage drop but as you said it doesn't seem to be so. What I have noticed it doesn't seem to do it twice in a row just the first time. So really strange.