Hey, I'm working on making me a homemade arduino. And wondered if this wiring diagram that I have created is correct?
wiring diagram:
click for larger image
P5 (USB TTL) is for a USB to serial converter.
Can't spot anything wrong.
Make sure the 100nF decoupling caps are right next to the relevant pins on the 328. Ground plane is
a good idea if making a PCB.
It doesn't have the clamping diode on RESET that turned out to be useful/necessary...
westfw:
It doesn't have the clamping diode on RESET that turned out to be useful/necessary...
A clamping diode, as D2 on this image?
MarkT:
... Ground plane is a good idea if making a PCB.
I was thinking the same thing @MarkT
A clamping diode, as D2 on this image?
Yes, that's the one. IIRC there wasn't a problem until the Uno made some subtle change elsewhere (pulldown before the cap?), and then it was "obvious" that it should have been there all along. So it might not be a problem on your board, but it's still a good idea.
I don't know if "wrong" is the right word. You have the serial RX & Tx grouped with other digital i/O.
I would separate it to a serial interface with the 6 lines that need to connect to the FTDI for communication
Are you aware of which 6 lines I am referring to ?
Have you used an FTDI to load sketches to a breadboarded ATmega328 before ?
. I don't see anything in this schematic that suggests there is an FTDI interface.
So is there one ? Have you done standalone ATmega328 programming (downloading sketches) before ?
@raschemmel, yes I think I know what 6 lines you're referring to. It is the first time I'll try to use an FTDI.
Her is an updated version:
click for larger image.
Do you know about installing the FTDI USB driver ?
Good choice of colours. Dark blue on black. 
Can't see anything wrong, but can't see anything right either!
Whats the battery voltage?
How much energy are you loosing with the liner regulator?
7805 is so...90s! There are better regulators these days.
For instance: http://uk.farnell.com/tracopower/tsr-0-5-2450/dc-dc-converter-5v-0-5a-sip/dp/2451540?ost=tsr0&selectedCategoryId=
@raschemmel. I see that my computer is preinstalled with libFTDI. An alternative to FTD2XX.
I ordered a FTDI Basic on eBay the other day. So when I get it, I hope I get it to work 
Have never tried it before.
Watcher:
7805 is so...90s!
That was news to me 9V, btw.
Tnx, @MarkT
White background:
click for larger image
I use FTDI Basic all the time, I get them from tinyosshop.com, $6.90.
Or a little more for modules to mount on cards, MIKROE483 from Mouser.
Both appear to use genuine FTDI parts, I have not had any issues with them and drivers that Win7 autoupdates.
@raschemmel. I see that my computer is preinstalled with libFTDI. An alternative to FTD2XX.
I ordered a FTDI Basic on eBay the other day. So when I get it, I hope I get it to work
I really don't know how the libFTDI would change anything. The reason you need an FTDI module is because it converts USB to TTL serial, which , if you are using a standalone ATmega328 is absolutely necessary, regardless of what libraries you have installed (AFAIK). Do you know where to get the FTDI driver ?
http://www.ftdichip.com/SupFTDI Drivers Installation Guide for Linux [PDF]
... FTDI VCP driver is built into the Linux kernel.
How to verify the built-in COM port:
- Plug in a FDI based design/module/cable
- Open a terminal window, and enter
- dmesg | grep FTDI
It looks like the virtual COM port driver is installed, but I'll test it out in a couple of weeks when I have the FTDI Basic.
@CrossRoads. This FTDI Basic from tinyosshop.com appears to be identical to the one I bought on eBay.
snes:
White background:
Wow! Can read it now!
Interesting question of whether the 3.3 V regulator should be powered from the 5 V regulator, or directly from the supply to the 5 V regulator. The latter is preferable as it reduces the load on the 5 V regulator.
Your CTS pin is floating on the connector. It needs to be jumpered to GND. My FTDI won't send without the CTS line active. TTL inputs float HIGH ,not LOW, so it should be grounded on the FTDI connector, which is probably because CTS stands for CLEAR TO SEND....
raschemmel:
My FTDI won't send without the CTS line active.
(Yet another) good reason to use an alternate USB-TTL chip then, as all the others have pull-downs sensibly included to default the logic.