Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [vga]

VGA stands for Video Graphics Array and originally provided a 640 × 480 maximum screen resolution.

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Why does VGA have so many ground pins (compared to DVI-I for example)?

If you look at the pinout for VGA, there are several ground pins: I was curious as to why, and I found this answer. To sum it up, the extra ground pins are so that each pin has its own ground in order to prevent interference in the analog…
user112513312
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What are 'return' pins?

On a VGA connector, there are numerous 'ground' pins. Three of these are Red return, Green return and Blue return; But why does each color component have its own ground pin?
Chris2048
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How is it possible to drive VGA displays at such high pixel clock frequencies?

I'm working on a digital circuit using discrete components to drive a 640x480 VGA display in a 80x30 text mode. For a 640x480 display, the pixel clock is 25.175MHz, which has a period around 40ns. I don't understand how I'm supposed to be able…
supershirobon
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VGA Output from Arduino

Is there any method to output VGA with Arduino?
littlebirdceo
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Ghosting in VGA signal generation

So, I'm generating a 1280x1024 (native screen resolution) VGA signal using a Lattice HX8K > Yosys, according to these timings, and a PLL of 107.812Mhz of Pixel Frequency. I then pass it through a simple scaler to achieve an effective pixel…
Hugo Sereno Ferreira
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How exactly does a VGA cable work?

I've been looking around on the internet and I can't find anything in depth on how the cable/connection functions. I've only been able to find simple pin out descriptions. If someone can link me or point me in the right direction, I would be very…
Josh Beckwith
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How to implement memory mapped IO

I am describing a system in VHDL. This system already contains a processor, a DDR SDRAM controller and a VGA controller. VGA reads pixels from SDRAM (already validated and proven in FPGA). Although VGA and SDRAM are already communicating with each…
hdhzero
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Is HSYNC required during VSYNC for VGA?

As a development to my previous question I am developing a protocol to drive VGA through lines originally designed for SPI communication. The problem is that I may be able to instruct the receiving decoder to have either VSYNC, HSYNC or color. This…
Anonymous
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Does VGA have to be drawn at 60hz?

I'm wanting to generate a VGA signal hopefully as painlessly as possible. I have an odd question though. Everywhere I see that VGA requires a 25MHz clock for the sync signals. Is it possible to just draw the screen slower? Like only refresh it at…
Earlz
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How Significant is VGA Impedance Matching?

I've seen a multitude of different resistor DAC solutions for a VGA signal, however they almost always have an impedance of >200 ohms per color, e.g. when I've been lead to believe that we want to match the 75 ohm input impedance of the VGA…
Connor Spangler
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How to utilize HDMI port on FPGA (basic)

Two questions. I have a Xilinx Spartan 6 FPGA which only has HDMI ins and outs. Is there some sort of guide or pre-written code that I can use to start sending images to the screen? I have no idea how to begin and I have not been able to find…
ballaw
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FPGA VGA Buffer. How to read and write?

I have an Altera DE2 board and trying to draw sprites. I am having some trouble implementing a screen buffer. I have a display entity that at a 25 MHZ rate outputs pixels for vga display. I was hoping to implement a buffer in SDRAM. The original…
Mikhail
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Do-It-Myself KVM?

I have several computers (desktops) in different geographical locations that I want to access remotely. Commercial KVM-over-IP solutions that I found are expensive (more than 200 euros each) and the cheapest ones do not support powering on-off…
tazmanos
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VGA interfacing with PIC

I'm looking for a way to control a VGA screen with a PIC. External components are OK, so a VGA chip with I2C or SPI or something is okay too. Requirements: Resolution: max 1024x768, no minimum Language: C (C18 compiler) or Jalv2 Only text, no…
user17592
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Can we attach LED to VGA port and make it light up, the same way we do in Parallel Port?

I just connected an LED to a parallel port in my PC and controlled it successfully through inpout32.dll I was wondering, if it was possible to do the same with the VGA port. Where can I find information about the functions and layout of the pins of…
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