[SOLVED] 16U2 on Arduino Mega Clone is blown,How to program the mega?

Development Tools IDE 1.x
1

I have a Mega clone which dosen't connect to th PC anymore. I tried to reload the 16U2 firmware on it which is located in arduino dir, but fail, the 16u2 is no resetting. signature is 0xffffff. so the 16u2 is dead.
I dont want to hook up a arduino as isp everytime to program the mega. Can I program it the following way ?

  1. remove the m328p on uno and connect reset from uno to reset on mega
  2. connect RX TX from the uno to the mega RX TX
  3. select the com port to which uno is connected,BUT select MEGA
  4. just click upload
    is this the way ?
    Should I remove the 16u2 from the board completely by desoldering? Even if i do that, I can' get another 16u2 in QFN package to replace.
2

First, wow, you actually have a clone with 16u2 :o Most have just a regular usb-serial chip.

  1. Yes, but don't forget GND :wink:
  2. Yes, don't cross RX and TX
  3. Yep
  4. Yesss, but depending on how the 16u2 failed it can interfere. You can try to pull it's reset (it has it's own reset line) low to keep it in reset. Or if you're sure it's dead, remove it. Or remove the resistors in the RX and TX line.

You can also just buy a random Serial-USB converter :slight_smile:

3

Ya,most boards have a CH340(??) something. I bought the clone for ~$15 with shipping
I removed the 16u2. Tried using it the above way and it worked. Something shorted with ISP header on the UNO while moving the boards and I fried second 16u2 today. FAIL!. now I am using a sparkfun Pro micro to make a usbtinyisp as a backup and I will be using it to program the boards .
Maybe, I'll program the pro micro as USB to serial interface until I find a store which has the 16u2 or 8u2 in stock. I won't buy these online, they tend to sell these chips three times the original cost if bought 10,000.
A Genuino UNO will be cheaper than the random USB to SERIAL converter my local shop sells.
Can you please tell me how to convert pro micro into USB to SERIAL converter ?
Shoud I use the serial communication sketch?
But how to stop the micro from resetting itself from the USB communication ?
It's a 32u4, adding a cap to reset pin won't stop it from resetting from USB.

4

You could probably make a sketch for it that reads characters in from Serial and outputs them on Serial1, and reads characters from Serial1 and outputs them on Serial. Give it a try.
I recommend having at least one USB-to-serial adapter on hand, to do Arduino work. Like this:
http://www.tinyosshop.com/index.php?route=product/product&product_id=600
If you get a Pro Mini in the future, it will just plug directly onto the Pro Mini for very easy programming. You should be able to use it as a way to program the Mega2560 as well.