cant communitcate with the arduino

hi im learning to design a pcb for my first project and put a arduino chip in instead of using the board, but im havint trouble communicating to the chip, i have my USB to TTL Converter installed with the correct driver but i cant seem to communicate or download anything to the chip. i am connedted on a serial port but just the usb to ttl converter.

im using the ATMEGA328 ARDUINO chip i have it all set up as it should be ive read a couple of guides, but on the com port all i can see id the usb to ttl converter, not the arduino chip, i have the +5, gnd, txd, rxd, from the port connected to the chip but no urduino?

i have a complete uno board also, but when i place the ic into the board it also doesnt recognise the chip as well?

any help greatly appreciated

ok found out i need to burn the bootloader on the ic, ive found the guide here and tryed several times using an uno board connected to breadboard followed the instructions, but cant seem to burn the bootloader, keep on getting an error does this guide actualy work, are there another guides out there that may work?

thank you


The Uno-ISP-bootloader situation is fraught with difficulties and work-arounds. I will probably get it from someone for having posted that. Makes a guy really appreciate those ICSP pins and the USBtinyISP.

IMHO.. there is no problems using Arduino as ISP.. -or- the Optiloader bootloader..

1.) please provide a wiring diagram and/or a picture of your your set-up.. sometimes we overlook things.. or have things backwards..etc.. (happens to everyone)

do you have ALL components/parts on the breadboard? including crystal & caps..etc...

what software/IDE are you trying to use? maybe try versions v22 or v23...instead of v1.0 if you are..

lets start there and see what we see...

first step is bootloader.. then we focus on uploading sketches..

To upload a program into an ATMEGA328 Chip with Arduino bootloader already in, You need :

  1. a USB -TTL board.
  2. Connect them right. What is your USB -TTL Adapter ?

Let take the one here : A FTDI breakout USB-TTL adapter.

But first, make sure the Arduino chip is connect right.

  1. The Vcc : pin 7 and pin 20. -- + 5 V
  2. The GND : pin 8 and pin 22 -- gnd
  3. The X-Tal : pin 23 and pin 24 -- 16 MHz Crystal and 2 X 22 pF cap to GND.

To connect the FTDI : For that particular board : RX --- > TX pin 3 TX --- > RX pin 2

And.... Connect the : DTR ---- > 0.1 uF cap -----> Reset pin 1 The cap is in serie.

In the IDE, choose the right USB port number and the right board. The board I choose is : Arduino Pro ( 5 V 16 MHz ) ATMEGA328.

Try it and see what happen...

If you have still problem, a picture of your setup will be nice.

thanks for the replys and info, i did try the guide here, but couldnt get that to work either

then i contacted the person who sold me the atmega 328 and USB -TTL board, and found out the bootloader was already installed, and managed to download data, simply by letting go of the reset button at the correct time. if i am able to download data using his method will i be able to burn the bootloader?

hi Techone, my setup is the same as you explain expect for the crystal, pins 9, 10 with the 22nf c's, the circuit diagram definatly says pins 9,10

Im confused?

is there a problem any more?

*There was/is a bootloader on it.. yes?

*You can 'now' upload sketches by manually pressing the reset button and timing the sketch upload in the IDE...yes?

What is the problem then?

uploading a sketch and burning a bootloader are two different things.. and use different pins.


Arduino >>> Standalone

RESET >>> DTR RX >>> RX TX >>> TX GND >>> GND 5v+ >>> 5v+


FTDI device >>> Standalone

RX >>> RX TX >>> TX GND >>> GND 5v+ >>> 5v+

then, when you hit upload in the IDE... wait for sketch/size to display at bottom.. then hit reset button on standalone circuit.


if your FTDI cables/device of choice has a RESET PINOUT... connect that to the DTR pin on your standalone device if it has one broken out for use.

At this point Im unclear as to what the problem is.. or what you want to do next?

Another bootloader "I" like is the Optiloader

hi Techone, my setup is the same as you explain expect for the crystal, pins 9, 10 with the 22nf c's, the circuit diagram definatly says pins 9,10

I am not worry about the 22 pF cap by not being there. My breadboard version don't have them anyway. So you did have a 0.1 uF in serie --> between the DTR and the RESET ? Yes ? With that cap there, no need to press the reset button during an upload of a new program. And what type of FDTI board you are using ? Because some type are : RX --- > RX and some are RX --- > TX.

But uploading a bootloader to a blank ATMEGA328, that one... can not help at this time.