SimonC
8/9/2012 9:55:28 AM
User Rank Beginner
Re: VGA and LEDs
I'm trying to configure the registers of the AD9980 using the I2C bus and my FPGA. I'm writing on the SDA and the SCL pins with a SCL-frequency of 100 kHz. However it doesn't seem to work. I'm trying but I don't think I wrote in the registers.
Anyone has some experience with this?
Any help would be greatly appreciated,
Simon
SimonC
8/8/2012 10:17:40 AM
User Rank Beginner
Re: VGA and LEDs
I think there is a problem with the AD9980 (see http://www.analog.com/static/imported-files/data_sheets/AD9980.pdf) because when I switch the resolution of a computer on 800 x 600 or on 1680 x 1050 , both at 60 Hz and feed this in the AD9980, the AD9980 keeps on outputting a dataclock with a period of 20 ns to the FPGA. While this period should be 6.79 ns for the 1680 x 1050 @ 60 Hz and 25 ns at 800 X 600 @ 60 Hz.
Is this normal?
SimonC
8/7/2012 12:44:34 PM
User Rank Beginner
Re: VGA and LEDs
I think I still have a problem with the exact timing. I have send you the code and the testbench.
Re: VGA and LEDs
if you get stuck send me a email with your code etc
SimonC
8/6/2012 5:31:09 PM
User Rank Beginner
Re: VGA and LEDs
Thanks, I'll keep on trying ;)
SimonC
8/6/2012 11:32:46 AM
User Rank Beginner
VGA and LEDs
Hi,
I 'm trying another home-made exercice ;) . I have connected a VGA input (another PC) to my FPGA and i'm trying to light some LEDs depending on the color of a pixel somewhere in the middle of a frame. I am using 800 X 600 @ 72 Hz resolution. I have read about VGA and I know I think I need 1040 pixels on a row and 666 pixelrows on a frame. (The pixelfrequency is 50 MHz. )
The VGA input on my FPGA delivers 8 bit for blue, 8 bit for red and 8 bit for green. a horizontal and vertical synchronisation signal. However when I make a colored frame (for example in 'paint' opening a black screen) , input this to VGA and assign for example the blue 8 bit vector on a specific pixel of the frame to the 8 LEDs, I get always '0' on my LEDs, even when I input a white or a blue frame.
I use the following principle: the first data that enters is a vertical blanc signal, followed by a horizontal blanc signal, followed by a row of screen-pixels, followed by a horizontal blanc signal, followed by a horizontal synchronisation signal (end of row 1). Then again a horizontal blanc signal, a row of screen pixels, a horizontal blanc signal and a horizontal sync (end of row 2),... etc. Every frame is concluded by a vertical blanc signal and a vertical synchronisation.
The specific timings for the signals, I found on this website: http://tinyvga.com/vga-timing/800x600@72Hz
Is this the correct way to do it? Or should you start with a synchronisation signal? Or start with the row of screen-pixels?
Thanks in advance,
Simon
SimonC
7/31/2012 5:22:37 AM
User Rank Beginner
Re: RS 232 and LEDS
I'll certainly follow up that one ;)
Made some code today for interfacing the PS/2 keyboard to some LEDs, tested it out and it works. Yeah!! ;)
There is one strange thing though, I have noticed that a few LEDs that are 'low', blink up for a very short time in between two characters I type with the keyboard.
SimonC
7/31/2012 5:11:37 AM
User Rank Beginner
Re: Communications
Totally agreed ;)
Re: RS 232 and LEDS
Glad it works ;) I will be blogging about it soon as part of vga controller I have been working on.
|
|
One of the things I've been wondering is whether or not the "okWireOR" module is really just a giant OR, or if the order in which things are attached matters.
I am shocked and horrified. It appears that those little scamps at Planet Analog are writing blogs pertaining to field-programmable issues.
This week's live online chat takes place on Thursday, May 23, 2013, at 1:00 p.m. ET.
Duane has decided that the time is ripe to get his ZedBoard bolted onto his robot with a Linux distribution up and running. That was the ultimate plan anyway, so why wait?
Would you class these as adages, aphorisms, axioms, dictums, epigrams, maxims, precepts, saws, truisms, or... well, what?
|
Tweet This
