Hot answers tagged

7

LCD displays use an external light source, and polarization of individual liquid crystal cells to allow / prevent light passing through. Pixels are not actually "lit", unlike in CRT or plasma displays. Thus, they really don't have any pixel element that could degrade with being on all the time. As a matter of fact, individual LCD pixels are not "on" or "...


5

Oh, you could use something like the below, but the micro would be a more elegant solution for sure. You can play with the value of R1 to get closer to the 30s if it matters. If you use a CMOS 555 then you can use a lower value capacitor and higher value resistor. This will directly drive up to about a 100mA backlight. If you need more current, add a p-...


5

There is a third mechanism for the degradation of an LCD: There is the anchoring layer, which is a thin layer of transparent material that is formed over the surface of the electrodes and onto which the ends of the Liquid crystals "anchor". This layer is often (but not always) a polyimide layer which has a "rubbing" to provide the correct orientation. The ...


5

You seem to have some confusion on a couple of different levels here. First of all, CR and LF are not "VT100 codes" as such, they're just ordinary ASCII control characters (hex 0D/decimal 13 and hex 0A/decimal 10, respectively). Actual VT100 codes are multi-byte sequences beginning with an escape (ESC) character (hex 1B/decimal 27), which is what your code ...


4

It is not possible to test the module without wiring it to a microcontroller. When power is applied to the module, the display remains off and uninitialized. In order to turn on the display, you need to initialize the display with certain commands and parameters. After which you can send characters to the display. This requires it to be wired to an ...


4

The "i80" parallel interface is simple and fast, and can be driven by external memory interfaces on some microcontrollers. However, it's a wide parallel bus, and requires a lot of pins to drive. SPI requires very few pins to drive, and is available as a hardware peripheral on many microcontrollers. It's slower than the parallel interface, though. The VSYNC ...


4

Another factor not yet mentioned is that while displaying a constant image on an LCD will not damage it, some LCDs may be damaged by images which flicker at a rate which coincides with the rate at which they switch drive polarity. It's possible to drive a pixel with positive or negative voltage, and the darkness of each pixel will depend upon the magnitude ...


3

About the only way to simulate grayscale using a 1-bit display is to do pixel averaging, e.g. using a square of four pixels to represent one pixel in the original image, 0 pixels on (white) = 0% 1 pixel on (light gray) = 25% 2 pixels on (medium gray) = 50% 3 pixels on (dark gray) = 75% 4 pixels on (black) = 100% Unfortunately, you don't have enough pixels ...


3

Hi Z stands for "seemingly almost nothing connected", it acts as an open circuit, so you should take care of that situation if you want the other circuit to function properly. Also, by the looks of it, 4.7k seems to be right in this scenario, as it would mean ~1mA at 5V, which is usually tolerable by most of the devices. You should take a look at the uC ...


3

I don't know if there are any TFT panels with LVDS interfaces that can work with zero porches, but usually they require at least some amount of non-active video pixels between active lines to know which pixel is first in line and long enough non-active period to understand which line is the first line. They do not use horizontal and vertical sync signals, ...


2

You can build your own graphics "driver" that integrates seamlessly with the Microchip Graphics Library, for any graphics LCD you have. I was able to use the graphics library with a different type of color LCD that the library did not support by default. The process is as follows: Download the Graphics LCD library from microchip Make a copy of an existing "...


2

There is no self test mode with the JHD12864E lcd, nor with the KS0108 compatible controllers. These lcds are always manufactured for production use, so it's expected that an appropriate test system (microcontroller) is setup by the end user. Since you say you don't want to mess around with your breadboard or wires, that's pretty much the answer, no. That ...


2

Unfortunately all of the LCD modules that I have worked with, whether they be graphic or character mode types, have required a "smart source" to check out whether they work. Sometimes you can be lucky with character mode types and connect them in place of an existing display on another piece of equipment to see if that can drive some content on the display ...


2

This company has TFT modules and English datasheets. http://www.crystalfontz.com/products/index-tft.html


2

These touches work as resistive touches. the resistance changes as a potentiometer between X1-X2 and Y1-Y2 that can be calculated and translated to the position. Very good tutorials are here and here. Just search google for "resistive touch screen theory of operation" and tones of answers are there.


2

If possible, I'd recommend to use 3V3 for the entire circuit; the ATMega is perfectly capable to operate at 3v3. But if you can't for some reason (if you already have a board that depends on 5v to work, or whatever), use the staple for level shifting, the TXB0108. Since it has just 8 lines you'll have to use probably 3 of them (for 18-bit rgb and other ...


2

So when I look at this I think of one circuit that you can trigger, push of a button, and it will output for a defined period of time and then turn off again until triggered again! The chip needed for this is a 555 Timer chip and will need to be set up in a monostable configuration, I used this circuit many times in my college days and it is very basic with ...


2

NE555 ? or even a transistor, resistor and a cap. Alternatively, you can put AND gate (or just few transitors) between !CS/!SS and any data line so when LCD is not getting any commands it can be used to control backlight (basically off for short moment you send data to LCD, and PWM when not sending any data to LCD)


2

As Wouter pointed out, you cannot directly write to a single pixel. The display matrix basically behaves as a monochromatic bitmap. It is physically divided between two identical controllers, one for the left half, the other for the right half. Their data/strobe lines are wired together and you can select the one to talk to by the chip select pins, CS1B ...


2

Maybe because the D/I pin is disconnected...? That pin is very much needed to make the LCD work - it's what selects whether you are sending Data, or Instructions to the LCD. If you don't tell it what kind of bytes you're throwing at it are, how can it hope to work out what to do with them? In your library it is known as the RS pin - Register Select. Some ...


2

Have you thoroughly inspected your PCB for shorts? You can use a continuity tester function (or the lowest ohm range) of a multimeter to test whether you have shorts between traces that shouldn't be shorted (do this with power disconnected!). Better if you do this test with the LCD (and any other socketed component) disconnected, so as to minimize ...


2

They are print and formatted print statements in the C language. See any C reference on printf() such as this one for the format string. Presumably xprintf is the same as printf except it sends the characters to the LCD rather than stdout, and xputs() is likewise similar to puts(). \x12 and \x13 are the escape sequences for fairly rarely used control ...


2

Well there are some things that may be deduced from the two pics you provided. What follows is just what I think about your module and it would be amazing if it was true. Do not take it as correct. Let's focus on your CN1 connector, the black one. Since this screen needs to be driven by something apart, I would say that connector is the interface to be ...


1

TTF is a vector font format, you first need to convert it into a bitmap with 1 bit color depth, then load it as an array in your code. GIMP can save the bitmap as a C array.


1

Edit: So the author already accepted an answer while I was still working on this. What this circuit offers over the 555 timer is higher timing precision and no dependance on component tolerances. Simplest way I can think of that uses easily sourced and cheap components is the following implementation of this diagram. 32.768kHz crystal into a TI CD4060B ...


1

The emWin library from Segger can do it. STM32 users have a free license to use it from ST (see here). It supports geometric shapes as you requested, but I should mention you can also make full GUIs with buttons, sliders, text boxes, etc. Unfortunately, according to this application note, only two sets of drivers are available with the free ST version: ...


1

The indicated display is electrically wired as two 64x64 displays which are placed side by side, and should be thought of in such terms. The data sheet does not provide any way of reading out the current value of X and Y registers, but your code should be able to keep track of what it has written to the display. The display does provide a function to read ...


1

The bottom left corner of section 4 of the datasheet explains how to connect the pot to VOUT, VDD, and V0.


1

You can do it by several way, using of your MCU(in this case ATMega128) by 3 or 3.3 volts using of Voltage divider and another way that i can't recall...


Only top voted, non community-wiki answers of a minimum length are eligible