Is it possible to upload a sketch to an ATMEGA328p pu with the usb2serial?

Other Hardware 3rd Party Boards
1

Hello people,

I tried to upload a sketch to an ATMEGA328p-pu (with the bootloader installed) with the USB2serial adapter, but i could not figure out how. I can select it in the arduino IDE on COM4, I installed the adapter driver, I connected the RX,TX,GND and 5V to the arduino on a breadboard but it still does not work. (it says 'programmer is not responding')

Does anyone know if it is even possible to upload a sketch like this. If yes; how?

Thanks!

Bas Peter

2

Hi, welcome to the forum.

I noticed that you didn't get an answer for your first question. Sorry :frowning:

With normal usb-serial adapters it is like this:
The DTR is used via 100nF to the reset. The DTR is used to reset the ATmega328P, and that starts the bootloader.
Those usb-serial adapters have pins labeled RX and TX. Sometimes connect RX-TX and TX-RX, but also try RX-RX and TX-TX.
Some usb-serial adapters have signals of 3.3V, in some cases that is not enough for an ATmega328P.

This is the Arduino USB 2 Serial : http://www.arduino.cc/en/Main/USBSerial
Some boards have pins, and this USB 2 Serial can be connected to those pins directly (without wires).
For a ATmega328P you still need the 100nF between the resets. And I think connect it with RX-TX and TX-RX.

Before using the USB 2 Serial, I would like to know if you ATmega chip is properly bootloaded and that it has a good circuit.
Did you buy a ATmega328P on Ebay with bootloader ? If so, I don't trust that bootloader.
Do you have a schematic or a photo to show how you have connected the wires to the ATmega chip ?
A 16MHz bootloader will only work with a 16MHz ATmega328P, and you need the two 22pF. And 5V and GND need to bee on both sided of the chip. Don't connect AREF to 5V. And so on....

3

Oh dear!

When in doubt, Gammon! :grinning:

Read it all through!

4

Thanks and no problem, I think I posted the question in the wrong section of the forum.

I bought two atmega328p-pu's of dealextreme without any bootloader. This because they were cheap and it is really easy to burn a bootloader to the atmega with a proper Arduino UNO.

I soldered the chip, a 1Mhz crystal, two 22pF cap's, a few resistors and some headers to a arduino protoshield and connected everything properly.

I hoped I could connect the usb2serial adapter to this to upload sketches to the Atmega.

I did actually connect AREF to 5v, I found this in the 'aruino on a breadboard' tutorial. I don't know if this could be the problem.

I bought the official arduino usb2serial adapter, so I will try the tips you gave me. I connected tx-tx and rx-rx, so that might be the problem....

Thanks a lot!

5

That is an error in that page. I know. Don't connect AREF to 5V.
I hope you have a 16MHz crystal, not 1MHz crystal :grin:

6

oh darn, stupid typo's. I used a 16Mhz crystal. :slight_smile:
Should AREF be connected to something else?

7

It actually worked with rx-tx, and the reset lines connected with a cap.

thanks a lot!

(i still dont really know what to do with AREF though :slight_smile: )

8

BasPeter:
(I still don't really know what to do with AREF though :slight_smile: )

Absolutely nothing!

(Except of course, a 0.1μF capacitor.)

9

Thank you Peter n for giving a good and proper answer.Providing the atmega with a seperate power supply and pressing the reset button at the correct moment while uploading helps.I was able to upload the program.
Thank You