Diy arduino

I would like to make arduino board,but I don't have crystal.I have Atmega328P-PU microcontroller WITH arduino uno bootloader,I don't own arduino board.I have some capacitors and resistors.Can it be runned without external crystal.If yes will it be 100% compatible with all the other programs.Thanks

As the chip is already loaded With the Uno bootloader, the fuses are likely set to expect an external crystal for creating the system clock.
You need to change the fuses to run from the internal 8 MHz RC circuit. To do that you need a Programmer connected to the ICSP pins, and a clock source.
Read here, scroll down to Alternate Clock Source:
http://www.gammon.com.au/breadboard

This will then leave you a bootloaded chip running at 8 MHz, compatible with other programs. You will need to select the appropriate board type for uploading sketches to go with the installed bootloader.

I have a 10.000 Mhz crystal,can it be used? Thanks

No, 10MHz crystal with ATmega328P-PU can be used but the bootloader is compiled for 16MHz (standard for UNO) so the uploading will not work.

Yes, use it as is.
Change boards.txt entry to reflect the different clock speed:

uno.build.f_cpu=16000000L

change to 10000000L

No guarantees, millis() and micros() and Serial speeds may be off still.

If you have only the chip, how will you download sketches?

This guy uses Arduino uno to burn bootloader,can bootloader be uploaded with USB TTL adapter with TX and RX. Thank you

The download via the bootloader could work at different speed 72000baud with original bootloader.

I think I'll take 16.00 Mhz crystal from NRF24l01 and hope my arduino will work.Also are there any boards available that are using SMD components,because I have alot of 0805 and 1206 capacitors and resistors

"can bootloader be uploaded with USB TTL adapter with TX and RX"

No, you need a Programmer to install the bootloader. The bootloader code then interacts with the PC (Rx/Tx) to load your sketch into memory.

"I think I'll take 16.00 Mhz crystal from NRF24l01 and hope my arduino will work." You are going to remove it and use it? That should work. Use 22pF crystals if you have them.

A lot of boards use 0805 and sometimes 1206 size parts. Look at a Promini or Nano for example. Common values with Arduino are 1K ohm, 10K ohm, maybe 270 ohm for transistor gates or LED current limit resistors, 0.1uF, 1uF, 10uF caps.

You can find them mixed with thru hole parts even, like I do on this '1284P board:

You could also just buy a resonator, ceramic resonator can remove the need of a crystal and the support capacitors, you just use it as is and its simple. Couple cents from digikey.

My problem is that this things are hard to get in Croatia and if I order them online it will take me 4 weeks to get.I paid for Atmega328p-pu like $10,original arduino uno costs almost $100 and raspberry pi (chepest) was like $150,really expensive.Currently im making a board for this thing in eagle,hope I'll be able to make it myself :smiley: however greetings from Croatia and thanks alot.

Nikola19992:
My problem is that this things are hard to get in Croatia and if I order them online it will take me 4 weeks to get.I paid for Atmega328p-pu like $10,original arduino uno costs almost $100 and raspberry pi (chepest) was like $150,really expensive.Currently im making a board for this thing in eagle,hope I'll be able to make it myself :smiley: however greetings from Croatia and thanks alot.

Did you try eBay? I thought it ships for free to whole Europe maybe except for Italy.