mipi dsi interface lcd display free sample

LCD can’t be driven with DC (Direct Current), it has to be driven with AC (Alternative Current) and the overall current has to be ZERO. Otherwise, the Liquid Crystal Material will be damaged sooner or later.

The Controller IC receives data written in ASCII or JIS code from the MPU and stores this data in RAM. This data is then converted into serial character patterns and transferred to the LCD driver IC.

MCU interface include two types, 6800 and 8080. 8080 is the much more popular than 6800. Generally, MCU interface consist of 4/8/9/16bits data (like DB0, DB1, , , DB7; Note: 8bits is the most popular bits width), CS (chip select), RS (data register or instruction register select), RD (read enable), WR (write enable).

RGB interface often been used in control large-scale high-resolution LCD display. It include 6/16/18bits data (like R0, R1, , , G0, G1, , ,B0, B1, , , ), VSYNC (Vertical synchronization), HSYNC (Horizontal synchronization).

Aimed at reducing the cost of display controllers in a mobile device. It is commonly targeted at LCD and similar display technologies. It defines a serial bus and a communication protocol between the host (source of the image data) and the device (destination of the image data)

DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). The interface is primarily used to connect a video source to a display device such as a computer monitor, and it can also carry audio, USB, and other forms of data.

DisplayPort was designed to replace VGA, DVI, and FPD-Link. The interface is backward compatible with other interfaces, such as HDMI and DVI, through the use of either active or passive adapters. It is mostly used for larger size and higher resolution displays.

A universal asynchronous receiver/transmitter (UART) is a block of circuitry responsible for implementing serial communication. Essentially, the UART acts as an intermediary between parallel and serial interfaces. On one end of the UART is a bus of eight-or-so data lines (plus some control pins), on the other is the two serial wires – RX and TX.

A Universal Serial Bus (USB) is a common interface that enables communication between devices and a host controller such as a personal computer (PC). It connects peripheral devices such as digital cameras, mice, keyboards, printers, scanners, media devices, external hard drives and flash drives. There have been four generations of USB specifications: USB 1.x, USB 2.0, USB 3.x and USB4.

HDMI (High-Definition Multimedia Interface) is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device. HDMI is a digital replacement for analog video standards.

RS-232, when compared to later interfaces such as RS-422, RS-485 and Ethernet, has lower transmission speed, short maximum cable length, large voltage swing, large standard connectors, no multipoint capability and limited multidrop capability. In modern personal computers, USB has displaced RS-232 from most of its peripheral interface roles. Few computers come equipped with RS-232 ports today, so one must use either an external USB-to-RS-232 converter or an internal expansion card with one or more serial ports to connect to RS-232 peripherals. Nevertheless, thanks to their simplicity and past ubiquity, RS-232 interfaces are still used—particularly in industrial machines, networking equipment, and scientific instruments where a short-range, point-to-point, low-speed wired data connection is fully adequate.

6) Power on the Raspberry Pi and wait for a few seconds until the LCD displays normally. And the touch function can also work after the system starts.

On December 2, 2021, the Raspberry Pi OS was divided into two branches, the Buster branch and the Bullseye branch. The Buster branch is a continuation of the old system and is more stable. The Bullseye branch added some new features, using open source libraries and new interfaces. Since the current Bullseye branch has just been released shortly, it is not stable yet. If you are an industrial user, it is strongly recommended to use the Buster branch.

If you are using the Buster branch system, the DSI LCD can work with Raspberry Pi directly after connecting and powering on. But if you are using the Bullseye branch system, you need to modify the config.txt as below:

Connect the Raspberry Pi camera to the CSI interface of the Raspberry Pi, power on the Raspberry Pi again, and after the system boots, execute the following command:

It has a thicker resistance than other colors, and it has a more brightness and width. One of the many thickness factors that are applied to mipi D LCD display is the more usefulness in this life. Mipi-interface Lcd display (MH)) has a more thickness resistance than other colors, allowing it to display different components. Mipi Dcd boards can provide high-quality performance, and a better gaming experience than the other one of LCDs.

Mipi Dimming LCD provides high, better graphics processing, and balancing functions of the components. It is possible to use Mipi Dimming ((IH)) in the front of and behind the majority of LCDs, it is high-precision and non-invasive displays, and it has a higher basic strength. Mipi DCD is a type of lcd display that has better performance than higher-Cinacityity (MC), and is not easy to use and even has a load-bearing capacity on the display panel.

Mipi D beads (LCD), a type of Mipi D beads connector on the front of a LCD panel and is used to display a variety of components. Now, ays the Mipi D beads (LCD), aip of Different colors (MH)), the transparency of the built-in lcd display and an amplifier of the LCD. With such a range of functions and can cater to different customer needs. When using a Mipi D beads board, the Mipi D beads (lcd display), the intrinsic part of the kit, and allows them to be used with a wide range of functions, to cater to different customer needs. As a wholesalers, Alibaba.com offers a wide range of Mipi D beads (lcd display), the mipi D beads (lcd display), for a more detailed version of Alibaba.

Shenzhen SLS Industrial Co.,ltd established in 2003, is a professional LCD module manufacturer and solution provider. We have 1 full-auto COG assembly line, 2 semi-auto assembly line, backlight assembly line, no dust TP bonding line and manufacturing tech support, we can provide unique, innovative and cost effective LCD module development and manufacturing. Our product range includes: middle-small size TFT LCD, industrial capacitive touch panel... Our LCD products have been widely used in communications, GPS, Equipment, electronic audio-visual, instrumentation, household appliances, PDA and other industries.

MIPI DSI has been widely adopted. It is ubiquitous in smartphones and also being used in tablets, laptops and laptop/tablet hybrids. It is also being implemented by the automotive industry for dashboard displays and in-car infotainment systems, and used in wearables, IoT and virtual/augmented reality applications.

MIPI DSI operates on the MIPI D-PHY physical layer. It uses a command set defined in the MIPI Display Command Set (MIPI DCS). It also incorporates the Display Stream Compression (DSC) Standard from the Video Electronics Standards Association (VESA). Overall, the feature set of MIPI DSI is quite similar to that of the more recent MIPI DSI-2℠ specification, which offers support for both MIPI D-PHY℠ and MIPI C-PHY℠.

Display size, contrast, color, brightness, resolution, and power are key factors in choosing the right display technology for your application. However, making the right choice in how you feed the information to the display is just as vital, and there are many interface options available.

All displays work in a similar manner. In a very basic explanation, they all have many rows and columns of pixels driven by a controller that communicates with each pixel to emit the brightness and color needed to make up the transmitted image. In some devices, the pixels are diodes that light up when current flows (PMOLEDs and AMOLEDs), and in other electronics, the pixel acts as a shutter to let some of the light from a backlight visible. In all cases, a memory array stores the image information that travels to the display through an interface.

According to Wikipedia, "an interface is a shared boundary across which two separate components of a computer system exchange information. The exchange can be between software, computer hardware, peripheral devices, humans, and combinations of these. Some computer hardware devices such as a touchscreen can both send and receive data through the interface, while others such as a mouse or microphone may only provide an interface to send data to a given system.” In other words, an interface is something that facilitates communication between two objects. Although display interfaces serve a similar purpose, how that communication occurs varies widely.

Serial Peripheral Interface (SPI) is a synchronous serial communication interface best-suited for short distances. It was developed by Motorola for components to share data such as flash memory, sensors, Real-Time Clocks, analog-to-digital converters, and more. Because there is no protocol overhead, the transmission runs at relatively high speeds. SPI runs on one master (the side that generates the clock) with one or more slaves, usually the devices outside the central processor. One drawback of SPI is the number of pins required between devices. Each slave added to the master/slave system needs an additional chip select I/O pin on the master. SPI is a great option for small, low-resolution displays including PMOLEDs and smaller LCDs.

Philips Semiconductors invented I2C (Inter-integrated Circuit) or I-squared-C in 1982. It utilizes a multi-master, multi-slave, single-ended, serial computer bus system. Engineers developed I2C for simple peripherals on PCs, like keyboards and mice to then later apply it to displays. Like SPI, it only works for short distances within a device and uses an asynchronous serial port. What sets I2C apart from SPI is that it can support up to 1008 slaves and only requires two wires, serial clock (SCL), and serial data (SDA). Like SPI, I2C also works well with PMOLEDs and smaller LCDs. Many display systems transfer the touch sensor data through I2C.

RGB is used to interface with large color displays. It sends 8 bits of data for each of the three colors, Red Green, and Blue every clock cycle. Since there are 24 bits of data transmitted every clock cycle, at clock rates up to 50 MHz, this interface can drive much larger displays at video frame rates of 60Hz and up.

Low-Voltage Differential Signaling (LVDS) was developed in 1994 and is a popular choice for large LCDs and peripherals in need of high bandwidth, like high-definition graphics and fast frame rates. It is a great solution because of its high speed of data transmission while using low voltage. Two wires carry the signal,  with one wire carrying the exact inverse of its companion. The electric field generated by one wire is neatly concealed by the other, creating much less interference to nearby wireless systems. At the receiver end, a circuit reads the difference (hence the "differential" in the name) in voltage between the wires. As a result, this scheme doesn’t generate noise or gets its signals scrambled by external noise. The interface consists of four, six, or eight pairs of wires, plus a pair carrying the clock and some ground wires. 24-bit color information at the transmitter end is converted to serial information, transmitted quickly over these pairs of cables, then converted back to 24-bit parallel in the receiver, resulting in an interface that is very fast to handle large displays and is very immune to interference.

Mobile Industry Processor Interface (MIPI) is a newer technology that is managed by the MIPI Alliance and has become a popular choice among wearable and mobile developers. MIPI uses similar differential signaling to LVDS by using a clock pair and one to eight pairs of data called lanes. MIPI supports a complex protocol that allows high speed and low power modes, as well as the ability to read data back from the display at lower rates. There are several versions of MIPI for different applications, MIPI DSI being the one for displays.

Display components stretch the limitations of bandwidth. For perspective, the most common internet bandwidth in a residential home runs on average at around 20 megabits per second or 20 billion 1s and 0s per second. Even small displays can require 4MB per second, which is a lot of data in what is often a tightly constrained physical space.

Take the same PMOLED display with the 128 x 128 resolution and 16,384 separate diodes; it requires information as to when and how brightly to illuminate each pixel. For a display with only 16 shades, it takes 4 bits of data. 128 x 128 x 4 = 65,536 bits for one frame. Now multiply it by the 60Hz, and you get a bandwidth of 4 megabits/second for a small monochrome display.

How many times did you start to plan a project and thought to yourself “if only I had a display that can fit within this design”? How many times did you alter the whole design because there were no displays available on the market that went with your idea?

If you’ve liked our standard display offer so far, you’ll be thrilled by what we can offer you now. It works like this: you send us your project information and display requirements, and we send you a free sample. Custom made and designed to fit perfectly within your project.

Different displays have different characteristics, just tell Panox Display your application, and operating environment, Panox Display will suggest a suitable display for you.

But Panox Display is not a school, if customers don`t know the basic knowledge to design circuit boards, we suggest using our controller board to drive the display.

First, you need to check whether this display has On-cell or In-cell touch panel, if has, it only needs to add a cover glass on it. If not, it needs an external touch panel.

If you don`t know or don`t want to write a display program on Raspberry Pi, it`s better to get an HDMI controller board from us, and Panox Display will send a config.txt file for reference.

I"m trying to find a 7" touchscreen compatible with the DSI interface. The board I"ve chosen for my CM4 has two DSI connection ports and ultimately I will use two identical touchscreens, one on each DSI port. I only require one to have touch functionality but having it on both would be a nice bonus!

I really don"t want to use the HDMI interface and would like to stick with DSI due to it"s low-power requirements and singular connection back to the raspberry pi.

That"s the only DSI touchscreen display compatible with the Raspberry Pi for far. For the display you will have to use a 22-pin DSI adapter (to 15-pin).

DSI displays (without touch) have been connected successfully (i.e. https://github.com/harlab/CM4_LCD_LT070ME05000) but touch part requires additional effort/not implemented yet.

If you want to connect your own DSI screen feel free doing so! As long as it is max 4 DSI-lanes, you have a suitable driver and overlay chances are good. But: don"t underestimate the effort it takes to get them working!

The only DSI display supported by the firmware is the Raspberry Pi 800x480 7" touchscreen, and then only one instance of it (IIRC you can choose whether that is connected to DISP1 (default) or DISP0).

We currently have overlays for the Pi 7" panel (vc4-kms-dsi-7inch), and JDI LT070ME05000 1200x1920 (vc4-kms-dsi-lt070me05000). Both are configured to use the DISP1 connector on the CMIO boards. vc4-kms-dsi-7inch could be tweaked to work on DISP0, but as that only supports 2 data lanes it won"t support LT070ME05000.

I have had an Ilitek ILI9881C (720x1280 or 800x1280) based panel running, and aBUGSworstnightmare is working with the TI SN65DSI83 DSI to LVDS chip with some LVDS panels.

If you don"t have a complete datasheet for your panel, then you have a huge task ahead of you. Debugging DSI is VERY hard in that if things are wrong then the panel just sits there dumbly and gives you no indication of what is wrong. Pi Towers is in the process of buying a DSI analyser to try and give ourselves a better chance at being sure that the Pi is doing what it is asked.

Even if you have a full datasheet, that is no guarantee that the panel/interface chip follows it. When investigating a Synaptics panel a while back we had to reverse engineer the commands that an HDMI to DSI bridge board was sending to the panel in order to create a working setup. It didn"t follow the datasheet.

Even me knowing all the dirty details of the panel under test, having all available TCON documentation on hands (data sheet, app notes, dedicated app not dealing with the MUX and DGC, etc) did not allow me to get the display to life; overlay was loaded, X working fine but pitch black screen. A DSI analyser is for sure a must have here from my POV, but only affordable for business use. So, good to hear that Pi Towers is investing in this.

Very good information, thank you so much! It sounds like of the 2 DSI connectors provided by CM4, 1 operates at a maximum of 4 lanes, and the 2nd operates at a maximum of 2 lanes. Not that big of an issue, having one display with a high quality resolution hooked up to the 4 lane port and then a much lower quality resolution hooked up to the other would be perfectly fine for my project.

Unfortunately it sounds like the DSI specification provided by raspberry pi hasn"t been well adopted, if at all, by manufacturers of PI hardware even though there seems to be an outcry for it from the community. I think I read in another forum post that only up until recently has the DSI spec on the PI been upgraded to 4 lanes on one of the ports. Maybe now more hardware will start rolling out for it since capabilities have expanded.

Nonetheless, this seems like a huge undertaking, especially for a novice like myself.. Sadly the bezel around the official raspberry pi dsi touchscreen is much too large. I must be able to fit my screen into a maximum of 100mm height by 178mm width..

Very good information, thank you so much! It sounds like of the 2 DSI connectors provided by CM4, 1 operates at a maximum of 4 lanes, and the 2nd operates at a maximum of 2 lanes. Not that big of an issue, having one display with a high quality resolution hooked up to the 4 lane port and then a much lower quality resolution hooked up to the other would be perfectly fine for my project.

2-lane DSI is able to support 1360x768, 3-lane is perfectly fine for 1920x1080 , so what is your understanding of "high quality resolution"? Some folks consider a high PPI as "high quality"..

Unfortunately it sounds like the DSI specification provided by raspberry pi hasn"t been well adopted, if at all, by manufacturers of PI hardware even though there seems to be an outcry for it from the community. I think I read in another forum post that only up until recently has the DSI spec on the PI been upgraded to 4 lanes on one of the ports. Maybe now more hardware will start rolling out for it since capabilities have expanded.

4-lane DSI , as well as the 2-lane DSI has been exposed on the Compute Module 1 already. CM did not saw that much attention because the "average noob" was not able to deal with them.

The CM4 is changing the story because the module itself offers WiFi/BT and Ethernet and the CM4IO and a huge range of third party platforms (thanks to the having the design files available un KiCAD) make using it as simple as a normal Pi. Advantage: dual CSI and dual DSI interface is available which offers a huge set of possibilities.

Nonetheless, this seems like a huge undertaking, especially for a novice like myself.. Sadly the bezel around the official raspberry pi dsi touchscreen is much too large. I must be able to fit my screen into a maximum of 100mm height by 178mm width..

Getting a DSI display to work on ANY platform is a "huge undertaking" for professionals too! Debugging DSI is a pain in the back and requires special - high expensive - tools.

So, if you need two 4-lane DSI (or even a 8-lane) stay away from RPi and use another SOC platform. Ohh .. Be warned ., they will be more expensive and more complex to use. And .. There is no simple/small baseboard for most cases.

Unfortunately it sounds like the DSI specification provided by raspberry pi hasn"t been well adopted, if at all, by manufacturers of PI hardware even though there seems to be an outcry for it from the community. I think I read in another forum post that only up until recently has the DSI spec on the PI been upgraded to 4 lanes on one of the ports. Maybe now more hardware will start rolling out for it since capabilities have expanded.

It is true that very few people had tried to use it, but that"s partly down to the complexity of DSI. It isn"t a plug and play interface in the way that HDMI, VGA, or DP are, and it"s more complex than DPI in that you have a command path that is frequently used to configure the panel/driver chip as well as sending it video data. It"s certainly beyond most hobbyists, and I don"t see that changing, largely because documentation on the panels is frequently lacking.

So, if you need two 4-lane DSI (or even a 8-lane) stay away from RPi and use another SOC platform. Ohh .. Be warned ., they will be more expensive and more complex to use. And .. There is no simple/small baseboard for most cases.

The asymmetry in CSI and DSI ports harks back to VideoCore"s origins in mobile devices. At least when the IP was being written you typically had a lower resolution front camera, and high res rear camera hence a 2 lane and 4 lane CSI interface, and likewise one high res main screen (4 lane) and potentially a smaller status screen (2 lane).

I guess my main concern here is that, yes I can find screens at these resolutions but an accompanying driver board to give DSI interface output to the CM4 seems impossible to find. Now that I have been enlightened it sounds like even with a driver board, software drivers will be another hurdle.

DSI interface has been speced by Mobile Industry Processor Interface Alliance - in short MIPI, and as indicated by the name targeting an interface spec for mobile applications. As such, there is no need for an "interface board".

Display is directly connected to the SOC without any glue logic. In case of the Broadcom devices the DSI is 2-lane and 4-lane as mentioned by 6by9. Don"t expect this to change in the near future as it requires a new SOC design (as said too).

For applications which don"t have DSI or which need different specs some companies have designed bridge IC, i.e. https://toshiba.semicon-storage.com/eu/ ... e-ics.html

So, as you want to use CM4 you can "easily" design your custom baseboard which has i.e. two ​TC358870XBG https://toshiba.semicon-storage.com/eu/ ... 40XBG.html connected to the HDMI interfaces. The CM4 will happily drive two (up to) 3840x2160, 30 fps, 24 bpp displays for you.

The following MIPI interface OLED and LCD panels already have firmware connectivity solutions. It may still require a custom FPC cable to meet specific project requirements:

I guess my main concern here is that, yes I can find screens at these resolutions but an accompanying driver board to give DSI interface output to the CM4 seems impossible to find. Now that I have been enlightened it sounds like even with a driver board, software drivers will be another hurdle.

I agree with others, if DSI screen, then I would take the original Raspberry DSI screen [I just write this posting in hospital with that display, but don"t use its touch functionality (that works) -- but touchpad of Logitech K400+ wireless keyboard instead]. @aBUGSwortsnightmare just helped me resolve "800x480 display too small for using gimp" issue via software:

I use 1024x600 HDMI no-touch 9" display without any issues (26$ inclusive(!) driver board and shipping from China). I really like 9" 1024x600 displays over 7" 1024x600 displays -- spending 10$ more you can even get 10" 1024x600 HDMI display with same driver (I switched driver boards between 9" and 10" displays and they work):

Beware of 7" 1024x600 displays that only have rgb666 colors (I have one from Waveshare). The 1024x600 9" and 10" displays cost less than the Waveshare one (45$), and have rgb888 colors!

FIGURE 1. The MIPI Alliance has defined a plethora of interfaces for use in mobile devices. This article focuses on the Display Serial Interface (DSI) shown in the upper left corner.

The MIPI Alliance is a consortium of mobile device manufacturers and electronics components vendors that was established in 2003 to specify a common set of interfaces for various sub-systems within smartphones and similar multimedia devices. They have published a range of standards covering interfaces to audio, camera, display, touchscreen and other devices as shown in their infographic (Figure 1).

One of these, the Display Serial Interface, or DSI, standard is starting to appear on readily available microcontrollers (MCUs) and displays. I have recently embarked on my first project that uses this interface, so it’s worth sharing some of what I have learned in the process.

The DSI is a high-speed serial interface between a host processor and a display module. It is designed for low pin count, high bandwidth and low EMI. We will focus on the basic features of the DSI physical layer, called the D-PHY and touch briefly on the next layer up, the Display Command Set or DCS. Figure 2 shows two ways DSI can be used. It can operate in video mode where RGB pixel data and horizontal and vertical sync signals provided by the display controller are encoded into the serial stream by the DSI Host and decoded by the Device to drive the display glass. Alternatively, if the display controller and graphics RAM are integrated into the display, DSI can operate in command mode where data being written by the MCU into the RAM is encoded on the interface. In either mode commands from the DCS can be transmitted to configure the display.

FIGURE 2. The DSI interface can operate in two modes – video mode in which the pixel data and synchronization signals are streamed to the display in real-time, and command mode in which pixel data is written to the graphics RAM integrated with the display controller in the display module.

The two data lane zero line, D0P and D0N, can take one of four states, LP-00, LP-01, LP-10 and LP-11. Certain sequences of these states are used to switch between three possible modes – control mode, high-speed transmission, and escape mode. Control mode is the idle state from which the other states begin and end. On power-up the DSI is in control mode and the LP-11 idle state.

FIGURE 4. Commands can be sent over Data Lane 0 using LP data transmission by first sending an escape sequence and then a Low Power Transmission Entry Command. Data is then sent in long or short packets as described in the text. Such communication is usually used to initialize the display at power up.

There is a lot more to the MIPI DSI interface that we don’t have space for here. This overview has hopefully given you a flavour for this interesting interface. It is a lot more complex than the classic parallel RGB plus clock and sync signals, but it requires a lot fewer pins and is capable of much higher bandwidth and therefore driving larger, high resolution displays.

6) Power on the Raspberry Pi and wait for a few seconds until the LCD displays normally. And the touch function can also work after the system starts.

The Display Serial Interface (DSI) is a specification by the Mobile Industry Processor Interface (MIPI) Alliance aimed at reducing the cost of display controllers in a mobile device. It is commonly targeted at LCD and similar display technologies. It defines a serial bus and a communication protocol between the host, the source of the image data, and the device which is the destination.

At the physical layer, DSI specifies a high-speed (e.g. 4.5Gbit/s/lane for D-PHY 2.0differential signaling point-to-point serial bus. This bus includes one high speed clock lane and one or more data lanes. Each lane is carried on two wires (due to differential signaling). All lanes travel from the DSI host to the DSI device, except for the first data lane (lane 0), which is capable of a bus turnaround (BTA) operation that allows it to reverse transmission direction. When more than one lane is used, they are used in parallel to transmit data, with each sequential bit in the stream traveling on the next lane. That is, if 4 lanes are being used, 4 bits are transmitted simultaneously, one on each lane. The link operates in either low power (LP) mode or high speed (HS) mode. In low power mode, the high speed clock is disabled and signal clocking information is embedded in the data. In this mode, the data rate is insufficient to drive a display, but is usable for sending configuration information and commands. High speed mode enables the high speed clock (at frequencies from tens of megahertz to over one gigahertz) that acts as the bit clock for the data lanes. Clock speeds vary by the requirements of the display. High speed mode is still designed to reduce power usage due to its low voltage signaling and parallel transfer ability.

The communication protocol describes two sets of instructions. The Display Command Set (DCS) is a set of common commands for controlling the display device, and their format is specified by the DSI standard. It defines registers that can be addressed and what their operation is. It includes basic commands such as sleep, enable, and invert display. The Manufacturer Command Set (MCS) is a device-specific command space whose definition is up to the device manufacturer. It often includes commands required to program non-volatile memory, set specific device registers (such as gamma correction), or perform other actions not described in the DSI standard. The packet format of both sets is specified by the DSI standard. There are Short and Long Packets, Short Packet is 4 bytes long; Long Packet can be of any length up to 216 bytes. Packets are composed of a DataID, Word count, Error Correction Code (ECC), Payload and Checksum (CRC). Commands that require reading data back from the device trigger a BTA event, which allows the device to reply with the requested data. A device cannot initiate a transfer; it can only reply to host requests.

Image data on the bus is interleaved with signals for horizontal and vertical blanking intervals (porches). The data is drawn to the display in real time and not stored by the device. This allows the manufacture of simpler display devices without frame buffer memory. However, it also means that the device must be continuously refreshed (at a rate such as 30 or 60 frames per second) or it will lose the image. Image data is only sent in HS mode. When in HS mode, commands are transmitted during the vertical blanking interval.