How do I program a homebrew Arduino?

Hi

As title really. I want to homebrew a really simple Arduino board. Without the FTDI/USB combo how is it programmed? Also I only have a laptop at the moment so USB is my only connection with the outside world.

Thanks Jim

I use an “FTDI Basic Breakout” board, which came with one of my Lilypad kits. I only need the one, usable only when I need to program each device, or when I want to power it from usb. Note that the breakout board I have is only a 3.3V one, which stops some of the LCDs I attach from working, as they want 5V, so when I am not using the breakout board I find other solutions for powering the microcontroller (eg, on one device I have an old Sony Ericsson charger giving it 5V, on another I have a solar charger that outputs 5V via step-up circuitry from its inbuilt LiPo battery, etc).

Thanks Ian.

So the breakout board isn't permanently attached to the homebrew Arduino?

Correct. Unless you leave it there because that's where you store it, or you have no other way of powering your project.

An easy way to get a programmer is to remove the processor from your arduino board, connect the TX, RX, 5V and GND to your homebrew, and upload as a regular arduino board. That's what I've been doing for at least a good part of a month before I told my cheap self go get a USB TTL board.

On the other hand, if you will, you can also remove the processor from the stand alone and plug into arduino to program it, pop it off and put it back into standalone. A zif socket may help.

Here is my blog post on this: http://liudr.wordpress.com/2010/12/12/how-do-you-program-your-standalone-arduino-chip/