I have 4/5 machines that I have been trying to use and they all seem to have the same issue.
4 of the machines are mac running osx 10.9-10.2. using an atmega256 r3 with the 16u2 chip.
When I plug the usb cable in, I get the cu.usbmodem and tty.usbmodem devices in the /dev folder, but only the CU device shows in the arduino IDE tools>ports menu.
If I choose the cu port, i can pull the board info, but I can not write a sketch, I just get an avr timeout.
I have tried installing ftdi drivers, upgrading boards in the boards manager, etc.
The board has a sketch on it, but once on it, I am unable to upload anything else. Even basic eeprom get().
I have been messing with this for a week and have made zero progress. Please help!!
wainwrid:
I have 4/5 machines that I have been trying to use and they all seem to have the same issue.
So the only comment element is the arduino board? That narrows down the issue.
wainwrid:
using an atmega256 r3 with the 16u2 chip.
Did you mean atmega2560?
wainwrid:
When I plug the usb cable in, I get the cu.usbmodem and tty.usbmodem devices in the /dev folder, but only the CU device shows in the arduino IDE tools>ports menu.
That's normal. The IDE filters out tty device names
wainwrid:
If I choose the cu port, i can pull the board info, but I can not write a sketch, I just get an avr timeout.
That validates you're able to communicate with the board through the USB to Serial chip. The problem is that avrdude is unable to communicate with the 2560. Either the bootloader is missing, is corrupted, or the 2560 is damaged.
wainwrid:
I have tried installing ftdi drivers, upgrading boards in the boards manager, etc.
FTDI drivers have nothing to do with the 16u2.
wainwrid:
The board has a sketch on it, but once on it, I am unable to upload anything else. Even basic eeprom get().
Was the last program you loaded doing a lot of serial? (Like a serial.print() inside of loop without any delay or other throttling?) You might try holding the reset button, plugging into the computer, hitting upload, and releasing the reset right as avrdude starts to run. (It helps if you turn on verbose output in the preferences so you can see exactly when avrdude starts to run.)
I did mean 2560. I am not entirely certain about the `16u2, my chip says mega2560 16AU 1549
this is a 2560 r3
This is good to hear. so I should just use the cu.modem?
The last sketch that was uploaded is the standard marlin build.
I have two boards that have this exact same issue. One is a chinese clone, which I have the ch340 drivers installed for. those drivers do work with my chinese clone uno R3.
I also have a genuine 2560.
Both 2560's have the same problem......
As an update I also tried to burn a bootloader via the gammon app on an uno and using the uno isp as the programmer.
This did not allow me to write a sketch or to burn a bootloader.
When I plug either of the 2560's in, pin 13 does blink.