70
votes
Accepted
How does my screen driver handle so much data?
Your calculations are correct in essence. For a 1440p60Hz signal, you have a data rate of 5.8Gbps once you allow for blanking time as well (non-visible pixel border in the image output).
For HDMI/DVI,...
- 70.7k
21
votes
Does VGA DB15 have the same pinout as VGA DE15?
Cannon, who invented the D-Subminature connector family, says the second letter indicates the shell size.
For standard density connectors a DA connector has 15 pins, DB is 25 (the original RS-232 ...
- 60.7k
20
votes
How does my screen driver handle so much data?
Modern computers are surprisingly fast. People will happily load up full HD 30fps videos without realising that that involves billions of arithmetic operations per second. Gamers tend to be slightly ...
- 47.1k
18
votes
Accepted
Why are OLEDs used in screens insted of LEDs?
Actually, many displays do use LEDs - but as far as I know, exclusively for extremely large displays. Just do a search for 'LED signage' and you'll see a whole sub industry around displays made from ...
- 29.3k
17
votes
LVDS vs MIPI, what's the difference?
I'd like to clarify some things:
LVDS standard describes a way to transmit 0s and 1s serially as voltage differences.
FPD-Link (and OpenLDI) standard describe a way to use LVDS to transmit video data....
- 271
17
votes
Accepted
Understanding memory requirements for an image file
Pixels per mm = 400/61.2 = 6.536
Yup.
Number of pixels in one image = 65.36 x 65.36 = 4272 pixels
Well, you mean pixels per icon. But even so, you cannot produce fractional pixels, so your number ...
- 61k
15
votes
Accepted
What kind of display is this?
Quadrophonic systems have four speakers. "Balance" therefore means you have to handle front to back as well as left to right.
The "balance" control on this system looks like a joystick.
The display ...
- 73.5k
14
votes
Accepted
Turn screen on/off with an N-channel MOSFET
I was wondering, if I use an N channel MOSFET like in the scheme
below, would an issue rise
Anywhere between likely and certain you will get problems with unwanted current down the HDMI 0 volts when ...
- 473k
12
votes
Convert from VGA 9 pin to RCA (manually - old machine)
There are a number of problems you have here:
VGA is 15 pins, not 9
RCA is composite video, not VGA
IBM 5151 is neither of those, it's an old standard "MDA" (monochrome display adapter).
...
- 47.1k
12
votes
Why do LCD screens need to refresh in the first place?
Some modern LCDs (especially ones built into phones and laptops) do kind of work this way; it's called "panel self refresh", which means that the display has its own memory that stores the ...
- 8,227
12
votes
Accepted
How do we control a 7-segment display with a rotary switch to ground and 12v supply?
There’s a less complicated way to do this. Since you only have six positions you could use a diode matrix.
Each segment is connected to the switch through diodes so that in position 1 the cathodes for ...
- 27.8k
11
votes
How does my screen driver handle so much data?
The link between display card and LCD panel is carried over several high-speed differential pairs using TMDS signaling, usually called "lanes". Typically four lanes are used, so one can say that the ...
- 42.4k
11
votes
Accepted
How does a microcontroller drive an LCD?
At some level a 320x240 display usually has 320 row drivers and 240 column drivers. These drivers are almost always provided by chips integrated into the displays (often on flex PCBs around two edges ...
- 3,751
11
votes
Understanding memory requirements for an image file
Make life simple for yourself by making the icons 64×64 pixels. Draw a border around them if you want them to look larger.
With the 16-bit color format, this only requires 8 kB per icon, or 400 ...
- 178k
11
votes
Does VGA DB15 have the same pinout as VGA DE15?
Terminology with these connectors can be a bit of a mess, originally the letter after the D identified the shell size, however it became common to use "DB" to refer to all of the standard ...
- 23.1k
10
votes
Does VGA DB15 have the same pinout as VGA DE15?
I highly doubt any VGA connection exists in size B with 15 pins. It is likely just a naming error as usual.
The standard connector is DE-15, size E with 15 pins in 3 rows.
- 172k
10
votes
Accepted
Why does VGA sync have 50 Ω drivers but 75 Ω cables?
To be honest, VGA sync wires are not generally 75 ohms like you expect.
Originally, the VGA did not have 75 ohm coax for sync anyway, so it did not matter. The document you are reading for video ...
- 172k
9
votes
Accepted
Why does this 7-Segment Display not function properly?
The 74LS47 shows the following:
$$
\begin{array}{ccccl}
D & C & B & A \\
0 & 0 & 0 & 0 & \rightarrow 0 \\
0 & 0 & 0 & 1 & \rightarrow 1 \\
0 & 0 & 1 ...
- 78.7k
9
votes
Accepted
What is the purpose of diodes in flip-dot displays?
If we redraw your circuit without the diodes, we have this:
simulate this circuit – Schematic created using CircuitLab
Now imagine you drive Column-1 High and Row-1 Low (and Column-2 and Row-2 ...
- 14.8k
9
votes
Understanding memory requirements for an image file
More about color depth
Expanding on Dave Tweed's answer, you can do even better than what he showed.
Here is the same large-size original he used:
Cropped to be square and shrunk to 64 x 64 pixels ...
- 315k
9
votes
Not understanding SSD1306 Oled display datasheet
Co is a continuation bit. If set to 1, the controller expects another control byte in this I2C write cycle. If set to 0, the controller will not expect to receive another control byte in this I2C ...
- 625
9
votes
Accepted
Russian к2лн641 VFD (Vacuum Fluorescent Display) driver pin out help
I'm Russian, so I'll help you out with this one.
First of all, the first link google gives when I search for that is the museum of soviet electronics. Interesting choice of parts haha.
Secondly, this ...
- 3,673
9
votes
Turn screen on/off with an N-channel MOSFET
You can use HDMI "hot plug detect (HPD)" to programmatically disconnect the monitor from the source. Disconnect the monitor side of the HPD and connect your own circuit to the source side ...
- 3,704
9
votes
Is this iPad screen flex cable glued onto the contacts?
This looks like an ACF (anisotropic conductive film) or ACP (anisotropic conductive paste) type bonding rather than the older (and usually low density) heat reflow technique.
It's heat bonded with a ...
8
votes
Understanding memory requirements for an image file
Each pixel will require 18 bits X 3 (for R, G and B) = 54 bits
Your estimate is incorrect. The "18 bits" value is per pixel, not per colour. The red, green and blue channels each have a maximum bit ...
- 8,681
8
votes
Why do LCD screens need to refresh in the first place?
The whole reason is the component circled in red below (Cs) which is a capacitor. Capacitors are really easy to manufacture, you only need two conductors and to space them apart with an insulator or ...
- 88.8k
7
votes
Is it necessary to use resistor when connecting backlight of 16x2 LCD display?
This is just a complementary answer for people facing this question for the first time (beginners or even non-beginners), like I did a few months ago when received a batch of no-name LCD modules ...
- 278
7
votes
Why does this 7-Segment Display not function properly?
From your table, it's pretty obvious that bit 1 is stuck on. Note that 0000 displays like 0010, 0101 like 0111, etc. This is likely a wiring error, probably a floating input.
- 315k
7
votes
Do HDMI/DVI and DisplayPort transfer only differences or full frames?
At least at lower resolutions and in the absence of "content protection", HDMI bears a surprisingly strong resemblance to analog video used with CRTs. A device to convert analog video to HDMI can ...
- 47.3k
7
votes
Are all pixels addressed simultaneously in one frame?
There are different technologies used for "computer screens".
Today's most common technology is TFT-LCD which mostly uses the Active Matrix adressing scheme to build up an image.
... is ...
- 81.4k
Only top scored, non community-wiki answers of a minimum length are eligible