Hello everyone!

Does anyone know about VGA signals? I searched on the web and found some Arduino libraries to generate composite video with Arduino. Then, I found an interesting article about creating VGA images with PIC. Since, the microcontroller in case runs at 2MHz, while Arduino runs at 16MHz, I tought is plausible to generate that signal with Arduino.

I got some results:

1 – Both CRT and LCD monitors detect the signal

2 – Only the CRT shows something flicking on the screen

But, my problem is with timers. I am using the delay() and micros() function, but they aren't accurate enough. Does anyone know how to use interrupts and timers to create a better accurate signal?


Tags: arduino, signal, vga

Views: 412

Reply to This

Replies to This Discussion

Hi Marcelo,

try using the Arduino Timer 1 http://arduino.cc/playground/Code/Timer1 library. Different from the usual timer library, this one uses the 16-bit timer of atmega328. You can have a precision up to 0.0625uS.


Almost there!

Yesterday I could keep a solid blue square on the screen for a few seconds, then it looses sync and come again few seconds later.

But as suggested, I had to use __asm__ and interrupt with timers.

Now, as a fried suggested, I will try the same code in an Arduino Mega, just to test the code and adjust with more precision.

Then, I will go back to UNO.

Hope to have good news soon!



Did you check this link before? http://www.tinyvga.com/avr-vga

It's an Atmega16 based vga project...

Thanks Fenando. This will certainly help.

Today I generate the highest freq signal I could with Arduino: 4MHz.

I did this to make the VGA from the bottom. Now I know how far can I go with it.

I will post the code on the blog.

Very good! I am just trying to understand why she has chosen the ATmega324. Any idea?

I will keep my efforts to do the same but using the ATmega328, or more/less specificaly, the Arduino. :)

My wish is give the opportunity to anyone generate VGA signal using their own Arduinos.

(If nobody has done this yet)

Hey Marcelo, that's my project that HaD linked to, there. The reason I chose an ATmega324 is because:

1) It runs at 20Mhz, and has 10Mhz I/O bandwidth. You need speed to push pixels in VGA. The expected pixel rate is 25.175Mhz, but we can give up some resolution and run a little slower than that.

2) Wide I/O. Unless you generate all your pixels procedurally, you need video memory to render from. Reading memory fast enough to push pixels at VGA rates means you need parallel access to it, and the ATmega324 has a lot of I/O pins. For 8-bit VGA color at a reasonable resolution, you need 16 bit addresses and 8-bit data, for 24 pins total. Then you also need a few other pins for sync signals and such. The ATmega324 is the smallest AVR I know that can meet all these requirements.

The reason some slower chips like the Propeller can generate VGA is because they aren't doing it with the system clock and system I/O. They have special subsystems for the video driving. 


Thanks for the reply. Now I understood. As I am going forward on my trials with Arduino, more I understand your choice :) . But, I will keep trying with Arduino to see how far I can go.

Please, take a look at the blog post I have just made: http://garagelab.com/profiles/blogs/arduino-generated-vga-color-signal

Any comments are more than welcome.

Thank you!!!


Latest Activity

GarageLab posted a blog post

Cooling things with an Infrared Laser

Lasers (Light Amplification by Stimulated Emission of Radiation) have a large industrial and…See More
Profile IconDavid Cofer, RITIU TRAIAN and MUNIR SADEQ OMAR OTHMAN joined GarageLab (arduino, electronics, robotics, hacking)
GarageLab posted a blog post

Nanowire Production New Method could Revolutionize Photonics Applications

University Wollongong, Australia, researchers just published, in Nanoscale Journal, a new method…See More
michae coley posted photos
GarageLab posted blog posts
Profile IconRaphael Enciso, Daniel Cerean, Naveed ur Rehman and 2 more joined GarageLab (arduino, electronics, robotics, hacking)
Nov 23
GarageLab posted blog posts
Nov 19
Profile IconTsan-Ming Chou, Jacqulyn Person and Paul joined GarageLab (arduino, electronics, robotics, hacking)
Nov 19
GarageLab posted blog posts
Nov 17
EEeng is now a member of GarageLab (arduino, electronics, robotics, hacking)
Nov 16
GarageLab posted a blog post

Android Robot

Android RobotEach year more and more investments is done to develop android robots that can make…See More
Nov 13
Profile IconNatalia and Andrew joined GarageLab (arduino, electronics, robotics, hacking)
Nov 13
GarageLab posted blog posts
Nov 12
Profile Iconcheck-iss and Christie joined GarageLab (arduino, electronics, robotics, hacking)
Nov 11
GarageLab posted blog posts
Nov 10
michae coley posted a photo
Nov 9
GarageLab posted a blog post

A New Module with Wi-Fi Connection is in Test

The ESP8266 Module revolutionize the world of the electronics fan being cheap and small solution to…See More
Nov 9
Profile IconDave, joshua salau, Alessandro Jose Stabellini and 1 more joined GarageLab (arduino, electronics, robotics, hacking)
Nov 9
GarageLab posted a blog post

A Robot Controlling a Switch

Residential automation are becoming more frequent on people life, and that’s what Tyler Bletsh did.…See More
Nov 6
GarageLab posted blog posts
Nov 5

© 2015   Created by Marcelo Rodrigues.   Powered by

Badges  |  Report an Issue  |  Terms of Service