Questions tagged [vga]

stands for Video Graphics Array and provides a 640x820 screen resolution.

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4answers
132 views

How can I make a mod for VGA cable to display only grayscale or Black & White?

My computer connects to the monitor using a VGA cable. I want to turn the display grayscale or black & white. I don't want to use any software solutions as I fear it will not be as effective as I ...
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2answers
313 views

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 ...
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2answers
986 views

Is this how a R-2R DAC for VGA should work?

I'm trying to wrap my head around if this is how a R-2R DAC should work. I say should for two reasons: (1) because I think I understand the theory behind the resistor ladder of subsequent voltage-...
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0answers
58 views

Schematic for TTGO VGA32 V1.2 by Lilygo

After recieving a couple of these boards to tinker with I have been searching online for some schematic. I have only found the following useful images: Block Diagrams with several pinouts described ...
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2answers
60 views

How I can resolve the problem of conversion (to_integer(unsigned(variable))

I want to solve a problem in VHDL with Quartus II. I made a model of VGA protocol 640/480. When I made the part of displaying I made one two signal in integer. Error (10621): VHDL Use Clause ...
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1answer
115 views

8-bit VGA DAC Design Question

I am being driven up the wall with designing an 8-bit VGA DAC for an embedded application. Everywhere I've researched highlights the necessity for "impedance matching" the 75 ohm termination ...
1
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1answer
71 views

Video RAM: How to create a shared bus for processor and VGA controller

I have a discrete video controller which reads a image from SRAM. The image should be written by a CPU. So I designed this circuit. I use two display RAM because I want to use double buffering. So ...
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1answer
78 views

Can an incorrect VGA timing kill a modern LCD screen?

I'm going to play with an Artix-7 dev board with a VGA port (Nexys 4 DDR from Digilent) and I'm a beginner at this. Assuming the pinout is correct, is it possible to destroy a (very) cheap modern LCD ...
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1answer
76 views

Looking for a display RAM for my VGA card [closed]

I´m designing a simple 800x600 pixel VGA card, based on this example (but I don´t reduce the image size). I also want to use a display RAM, so a microprocessor can write a new image. For this I need ...
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2answers
76 views

Trick monitor into receiving signal [duplicate]

I have the plan to convert a few old LED backlit monitors into false windows. While I theoretically could buy direct LED drivers to power these panels, I'd prefer to keep the existing circuitry, since ...
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2answers
205 views

How to calculate resistor values for a VGA DAC

I have an FPGA and want it to drive a VGA monitor. I want more than 3 bits of color so I need a DAC of some sort. So I want to make a resistor dac. My plan is to have 3 bits per subcolor. So total of ...
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1answer
102 views

Un-moving “static” image from VGA controller

I am reverse-engineering a daughter card which uses a ADV7125KSTZ140 VGA video DAC driven by a FPGA. The FPGA is a Xilinx Spartan 3E programmed by an off-board processor using slave-serial mode, ...
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0answers
21 views

Quartus Prime Lite: Generate a 25.18 MHz clock and Constrain to clock input in HDL

I am trying to use a generated clock in .sdc to drive my logic in my DE1-SoC Cyclone V chip. When I load the design onto the chip currently, nothing happens. My counter led does not even blink to show ...
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0answers
78 views

How to convert arcade RGB video (2-5v p-p) to VGA (0-0.7v)?

I'm trying to convert arcade video signals (JAMMA) to VGA specifications. From what I've gathered, arcade video signals aren't standardized. They can range from 0v-2v or 0v-5v, etc. However, VGA ...
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1answer
40 views

Ribbon Connector And Custom Graphics Card

I understand how to make a homemade VGA connection using resistor ladders or ICs, like is done in this tutorial. http://dqydj.net/how-to-produce-640x480-vga-color-video-from-an-arduino/ Is there any ...
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1answer
102 views

Identifying Feature on VGA PCB

I am reverse-engineering a board which provides a VGA output signal for connecting an oscilloscope to an external monitor. I have quite a bit of experience with PCB design but there is a feature on ...
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4answers
1k views

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 ...
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1answer
50 views

Is it possible to know CRT monitor VGA wires that have no color standards

Actually I know that rgb wires are thicker than the others also they r coax wires. But how to destinguish Vsync and Hsync wires and the respective ground wire for each signal when the wire colors ...
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1answer
118 views

VGA timing difference in pixel frequency

I'm trying to determine what is the correct timing for 640x480 VGA. Using Tinyvga.com for 640x480@60Hz I get a pixel frequency of 25.2 Mhz and not 25.175 Mhz. 800*525*60 = 25200000 I have wrote ...
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2answers
88 views

FPGA: possible to use PC as I/O?

I'm a beginner in FPGAs and I would like to implement a basic CPU with a simple VGA display. If I have a FPGA that has USB-UART could I use my own PC monitor as a display? What about sending input ...
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2answers
2k views

VGA to composite circuit. Does it work?

So I found a VGA to composite passive converter circuit online, and was wondering if it would work, if the vga timings were modified to match the timing of composite. Here is a relevant schematic:
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2answers
436 views

Unable to figure out VGA [Verilog]

After doing plenty of research on how to generate VGA signals and looking at a few code examples, I attempted to write my a simple VGA signal generator that just displays a single solid color on the ...
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2answers
63 views

Fitting USB Data in Cat5 Cable with External Power

I have a camera system at home with a DVR, which connects to a VGA monitor and mouse with which you can read and edit its settings (the cameras can be accessed over the Internet). I've been trying to ...
5
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1answer
625 views

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 ...
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2answers
444 views

VGA cable arcing against computer case

I've tried to turn on my old PC with my old LCD monitor, which is powered by a kettle cable directly from mains, no power supply brick). When trying to get it to work, I have noticed the following ...
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3answers
413 views

YPbPr, VGA, Basys3

The Basys3 (a Digilent FPGA) manual says that the VGA analog outputs can drive between 0 and 0.7 volts. Does anyone know if, from a purely analog perspective, this can drive “component video”, ...
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2answers
273 views

VGA impedance matching

i have VGA in one side of my circuit and I want to connect that to a connector with 50 ohm impedance. after that I must convert 50 ohm impedance to 75 ohm, because I have a vga cable in other side. in ...
1
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1answer
261 views

Vivado Video IPs not working as expected

I've been trying to understand how to utilize AXI-Stream IPs for Video processing and display via VGA for a few days now, but can't seem to get any circuit to work. Here is a test circuit I created: ...
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2answers
780 views

Using old laptop LCD as external VGA screen [closed]

I have a few old laptops with good LCD panels that I wish to salvage and use as external VGA screen on other computers. I'am no expert in electronics but I work with computers and know the basics of ...
1
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1answer
992 views

Resistor DAC and buffer for VGA output

I'm in the process of designing a very simple binary weighted resistor DAC for an output stage of a RGB VGA driver. There will be 3 bits for R and G components and 2 for B. The output signal is analog ...
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1answer
399 views

how to show a picture on monitor through VGA from basys3 [closed]

I must find a picture and upload it into my basys3 board then I must show it on monitor through VGA cable. I dont know how to do that. What are the steps I must take?
5
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1answer
736 views

Why doesn't my VGA implementation using an AVR microcontroller work?

Problem I'm trying to generate the appropriate signal output for interfacing an AVR ATmega328P microcontroller with an LCD monitor, via the VGA specification. The VGA specification I am trying to ...
0
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1answer
276 views

VGA Output for 640 x 360 (16:9) Display for LCD monitor [closed]

I'm currently designing a TTL-based device to output VGA signals to a 16:9 aspect ratio LCD Monitor with a frame rate of 60 Hz. I hove mostly been referring to this question on how the VGA protocol ...
3
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1answer
104 views

Character mask VGA display

Im building a VGA (640x480@60Hz) adapter for my homebrew project but i dont have enought memory to store a framebuffer. Since im using 8 bit memory i plan to do 8 bit color, but 8 colors would be ...
1
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1answer
403 views

FPGA based VGA controller to drive PC monitor

I have implemented a VGA controller in FPGA, for 800x600 resolution @60Hz. Can I use it to drive a PC monitor ? In the PC's monitor resolution settings, it's seen that it supports multiple resolution ...
0
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1answer
133 views

s25fs256s serial flash not responding with RTD2660

Hello guys,, I am interfacing RTD2660 with s25fs256s serial flash using SPI. but when i send the command_type(0x46 (comman instruction type is read)) and command_data(0x9f (command for ...
1
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1answer
1k views

EGA display converting to VGA - screen's shaking

I've recently tried to make conversion from EGA (probably, couldn't get scope to verify) to VGA to replace an old factory CRT monitor to LCD. Screen displays fine but it appears to shake vertically ...
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3answers
297 views

VGA Image Refreshing

Hey everyone I am looking into VGA protocol. I have researched a lot but only thing I could not figure out is this: Does VGA vertical sync and horizontal sync needs to be sent over and over to keep ...
0
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1answer
554 views

YPbPr to VGA (consoles on monitor)

So the main idea is to take the component video of my consoles and convert them to VGA using the LM1881 IC, to strip the sync signal. If I was going to plug the green cable from my PS2 component into ...
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0answers
1k views

4-bit parallel data bus using DMA and GPIO on STM32?

It's possible to generate 8 or 16-bit parallel output on an STM32 by using DMA to transfer from a buffer to the ODR register of a GPIO port, by transferring either a byte or a word at a time. However ...
0
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1answer
419 views

Modifying VGA Controller For My Monitor

I saw this VGA demo for a 640x480 monitor http://pumpingstationone.org/2013/04/nerp-fpgaok/ and I would like to run it on my monitor using a Basys-3 FPGA. The GPIO demo code for the Basys-3 board ...
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2answers
319 views

Why does this JFET attenuator distort the signal this way?

I have been trying to build a simple VGA using an op-amp and JFET for gain control. I get good results over a small range of voltages (like factor of 10) but as soon as I try to improve this, the ...
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2answers
159 views

Pic32MX Clock too slow

Using pic32mx340F512H and XC32 compiler and ICD3 debugger on MPLAB. So I'm working on displaying colors on a screen using VGA protocol and, thus, need to max the clock speed. The standard for a pixel ...
0
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1answer
191 views

VHDL/FPGA Should I block down an array into arrays of dimensions with powers of 2?

I'm building a VGA display with a Xilinx FPGA. I'm not exactly sure what's the best way to store VGA frames. The resolution is 640x480. Should I just use a 640x480 2D array or block 640x480 into ...
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3answers
164 views

detect VGA port (through pinout) and send a command to microcontroller

How can i realize that a video project is connected to laptop through a VGA port?? I think I can understand it from the VGA pinout; but i don't know which one?? If I realize it then I can send a ...
1
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2answers
369 views

Converting 100MHz clock to 65MHz clock for VGA

I've written some HDL code to convert the frequency of the clock on FPGA (100MHz) to a freqency which is compatible with my VGA monitor (65MHz): ...
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0answers
1k views

Debugging FPGA VGA connection

I want to display images on the screen and to do this I used this git and this article as references. The specs of my screen are 1280x1024, including porch pixels the dimensions are 1688x1066. From ...
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0answers
163 views

What do these labels mean in the context of VGA timings?

This is the image provided with the De1 SoC development board. I do not know what some of the abbreviations mean in this context VGA_R [7..0] values for red pixels VGA_G [7..0] values for ...
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0answers
145 views

Unable to use the VGA port correctly, De1 Soc distorts signal depending on the output pin

This is a followup to my previous question. The code I was using, pin assigmnets and the theoretical timings for VSYNC and HSYNCH were correct. I have used to oscilloscope to look at the signals, ...
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0answers
420 views

Troubleshooting FPGA VGA connection

I have DE1 Soc development board. I have been following this youtube video in order to start casting some stuff onto the screen. I am unable to display anything on the screen at the moment unless ...