ARDUINO + LM1881 = OSD?

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi guys,

I am new on arduino's, but old on PIC, and I found this very cool project on the internet:

he uses the ATMEGA8 directly.... with an 14.7456 MHz crystal... and arduino uses ATMEGA168 @ 16MHz, here is one source of my problems.

The other problem is the code being used on the arduino.

I did some modifications on his code, after looking a lot of datasheets... but I might be missing something here....

Code is on this URL:

http://www.moraesgyn.webs.com/

My TV screen:

I wish my TV looked like this:

Btw I had do comment this part out of wiring.c

/* comment this
SIGNAL(TIMER0_OVF_vect)
{
      timer0_overflow_count++;
      // timer 0 prescale factor is 64 and the timer overflows at 256
      timer0_clock_cycles += 64UL * 256UL;
      while (timer0_clock_cycles > clockCyclesPerMicrosecond() * 1000UL) {
            timer0_clock_cycles -= clockCyclesPerMicrosecond() * 1000UL;
            timer0_millis++;
      }
}
*/

and the schematics on Gary´s website is wrong:

the pin that goes on the video out put is not the PB0/ICP...
the right pin is the PD7/AIN1....

I used this to guide me thru the pins:

Hope someone could help me calculate this new values for the clocks...

Timing is really hard to deal when you don't have an oscilloscope...

Thanks in Advance,

Tony

2

Hi Antonio Santos,

Did you ended having success with this?
This is one of the main reasons I'm starting with arduino.

Thanks,
Nando

3

Hello Nando,

welcome aboard, I ended up side tracked by my work, and I did not do much after that. As you can see, there was a problem with the original Schematic, and you also have to make some modifications on the wiring.c file.

I would love make this project work... there are some projects with the MAX7456, but its a really expensive chip... I leave in brazil, so it costs about 50 dollars down here...

I think we need someone with knowledge in Video signals, and a osciloscope to help us on this project...

let me know of your findings....

Tks,

Tony

4