lcd screen hat free sample

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

Display HAT Mini features a bright 18-bit capable 320x240 pixel display with vibrant colours and formidable IPS viewing angles, connected via SPI. It"s got four tactile buttons for interacting with your Pi with your digits and a RGB LED for notifications. We"ve also squeezed in a QwST connector (Qwiic / STEMMA QT) and a Breakout Garden header so it"s a doddle to connect up different kinds of breakouts.

It will work with any model of Pi with a 40 pin header, but we think it goes with the Raspberry Pi Zero particularly well - we"ve included a pair of standoffs so you can use to bolt HAT and Pi together to make a sturdy little unit. To accommodate the screen Display HAT Mini is a bit bigger than a standard mini HAT or pHAT - it"s around 5mm taller than a Pi Zero (so a Mini HAT XL or a Mini HAT Pro, if you will).

Display HAT Mini lets you turn a Raspberry Pi into a convenient IoT control panel, a tiny photo frame, digital art display or gif-box, or a desktop display for news headlines, tweets, or other info from online APIs. This screen is a handy 3:2 ratio, useful for retro gaming purposes!

To get started, follow the installation instructions in the Display HAT Mini library. This library contains some examples of how to use the screen, buttons and LED with Pygame. You can also find examples for this screen in our ST7789 Python library, these show you how to write and draw on the screen using PIL to display shapes, text and gifs.

We"ve also been having fun with fbcp-ili9341 - a high level framebuffer driver for SPI-based LCD displays. The Raspberry Pi OS desktop is a leeetle small on a 2.0" screen, but this might be a good option if you"re doing something like building your own custom retro console.

If you have a Breakout Garden breakout without a Qw/ST connector, you can either pop one of these adaptors on the end of your cable, or you can plug a Breakout Extender into the header at the other end of Display HAT Mini (you can find it next to your Pi"s SD card slot).

The buttons are close to the edge of the screen, so it"s worth taking a bit of care when pressing the buttons that you"re not also pressing down on the screen, particularly at the edge with the ribbon cable.

Please note that because of Display HAT Mini"s extra size, it will overhang adjacent slots on expansion boards like pHAT Stack, Black HAT Hacker, HAT Hacker HAT and Flat HAT Hacker. No shame - every HAT is valid, every HAT is beautiful.

We"ve found two standoffs to be sufficient to keep this HAT firmly in place, but if you want to add standoffs at every corner of your Zero so you can use it to stop a tank or something you can pick up more here.

A 128x64 pixel, 2.15" LCD display with snazzy six-zone RGB backlight and six capacitive touch buttons. GFX HAT makes an ideal display and interface for your headless Pi projects.

GFX HAT riffs off our beloved Display-O-Tron HAT, but gives you the flexibility of individual pixels, letting you display more complex graphics and real typefaces, while retaining the handy capacitive touch buttons for input/navigation.

Our Python library handles displaying on the LCD, controlling the backlight, and linking functions to the touch buttons. We"ve also included a couple of examples to get you started.

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

Raspberry Pi leads out 40 GPIO pins, while the screen leads out 26 pins. When connecting, pay attention to the corresponding pins and Raspberry Pi pins.

5) Insert the TF card into the Raspberry Pi, power on the Raspberry Pi, and wait for more than 10 seconds to display normally. But the touch is abnormal at that time, and the touch needs to be calibrated as the following steps.

3. After reboot, touch will work normally under normal circumstances. But for different resistance screens, the accuracy of using the default calibration parameters may not be very suitable.

You can perform touch calibration by clicking the Raspberry Pi icon on the taskbar, selecting Preferences -> Calibrate Touchscreen, and following the displayed prompts.

In these videos, the SPI (GPIO) bus is referred to being the bottleneck. SPI based displays update over a serial data bus, transmitting one bit per clock cycle on the bus. A 320x240x16bpp display hence requires a SPI bus clock rate of 73.728MHz to achieve a full 60fps refresh frequency. Not many SPI LCD controllers can communicate this fast in practice, but are constrained to e.g. a 16-50MHz SPI bus clock speed, capping the maximum update rate significantly. Can we do anything about this?

The fbcp-ili9341 project started out as a display driver for the Adafruit 2.8" 320x240 TFT w/ Touch screen for Raspberry Pi display that utilizes the ILI9341 controller. On that display, fbcp-ili9341 can achieve a 60fps update rate, depending on the content that is being displayed. Check out these videos for examples of the driver in action:

Given that the SPI bus can be so constrained on bandwidth, how come fbcp-ili9341 seems to be able to update at up to 60fps? The way this is achieved is by what could be called adaptive display stream updates. Instead of uploading each pixel at each display refresh cycle, only the actually changed pixels on screen are submitted to the display. This is doable because the ILI9341 controller, as many other popular controllers, have communication interface functions that allow specifying partial screen updates, down to subrectangles or even individual pixel levels. This allows beating the bandwidth limit: for example in Quake, even though it is a fast pacing game, on average only about 46% of all pixels on screen change each rendered frame. Some parts, such as the UI stay practically constant across multiple frames.

Good old interlacing is added into the mix: if the amount of pixels that needs updating is detected to be too much that the SPI bus cannot handle it, the driver adaptively resorts to doing an interlaced update, uploading even and odd scanlines at subsequent frames. Once the number of pending pixels to write returns to manageable amounts, progressive updating is resumed. This effectively doubles the maximum display update rate. (If you do not like the visual appearance that interlacing causes, it is easy to disable this by uncommenting the line #define NO_INTERLACING in file config.h)

The result is that the SPI bus can be kept close to 100% saturation, ~94-97% usual, to maximize the utilization rate of the bus, while only transmitting practically the minimum number of bytes needed to describe each new frame.

This driver does not utilize the notro/fbtft framebuffer driver, so that needs to be disabled if active. That is, if your /boot/config.txt file has lines that look something like dtoverlay=pitft28r, ..., dtoverlay=waveshare32b, ... or dtoverlay=flexfb, ..., those should be removed.

This program neither utilizes the default SPI driver, so a line such as dtparam=spi=on in /boot/config.txt should also be removed so that it will not cause conflicts.

Likewise, if you have any touch controller related dtoverlays active, such as dtoverlay=ads7846,... or anything that has a penirq= directive, those should be removed as well to avoid conflicts. It would be possible to add touch support to fbcp-ili9341 if someone wants to take a stab at it.

If you have been running existing fbcp driver, make sure to remove that e.g. via a sudo pkill fbcp first (while running in SSH prompt or connected to a HDMI display), these two cannot run at the same time. If /etc/rc.local or /etc/init.d contains an entry to start up fbcp at boot, that directive should be deleted.

When using one of the displays that stack on top of the Pi that are already recognized by fbcp-ili9341, you don"t need to specify the GPIO pin assignments, but fbcp-ili9341 code already has those. Pass one of the following CMake directives for the hats:

-DFREEPLAYTECH_WAVESHARE32B=ON: If you are running on the Freeplay CM3 or Zero device, pass this flag. (this is not a hat, but still a preconfigured pin assignment)

-DPIRATE_AUDIO_ST7789_HAT=ON: If specified, targets a Pirate Audio 240x240, 1.3inch IPS LCD display HAT for Raspberry Pi with ST7789 display controller

-DKEDEI_V63_MPI3501=ON: If specified, targets a KeDei 3.5 inch SPI TFTLCD 480*320 16bit/18bit version 6.3 2018/4/9 display with MPI3501 display controller.

If you connected wires directly on the Pi instead of using a Hat from the above list, you will need to use the configuration directives below. In addition to specifying the display, you will also need to tell fbcp-ili9341 which GPIO pins you wired the connections to. To configure the display controller, pass one of:

-DILI9341=ON: If you are running on any other generic ILI9341 display, or on Waveshare32b display that is standalone and not on the FreeplayTech CM3/Zero device, pass this flag.

-DILI9486L=ON: If you have a ILI9486L display, pass this directive. Note that ILI9486 and ILI9486L are quite different, mutually incompatible controller chips, so be careful here identifying which one you have. (or just try both, should not break if you misidentified)

-DGPIO_TFT_DATA_CONTROL=number: Specifies/overrides which GPIO pin to use for the Data/Control (DC) line on the 4-wire SPI communication. This pin number is specified in BCM pin numbers. If you have a 3-wire SPI display that does not have a Data/Control line, set this value to -1, i.e. -DGPIO_TFT_DATA_CONTROL=-1 to tell fbcp-ili9341 to target 3-wire ("9-bit") SPI communication.

-DGPIO_TFT_RESET_PIN=number: Specifies/overrides which GPIO pin to use for the display Reset line. This pin number is specified in BCM pin numbers. If omitted, it is assumed that the display does not have a Reset pin, and is always on.

-DGPIO_TFT_BACKLIGHT=number: Specifies/overrides which GPIO pin to use for the display backlight line. This pin number is specified in BCM pin numbers. If omitted, it is assumed that the display does not have a GPIO-controlled backlight pin, and is always on. If setting this, also see the #define BACKLIGHT_CONTROL option in config.h.

fbcp-ili9341 always uses the hardware SPI0 port, so the MISO, MOSI, CLK and CE0 pins are always the same and cannot be changed. The MISO pin is actually not used (at the moment at least), so you can just skip connecting that one. If your display is a rogue one that ignores the chip enable line, you can omit connecting that as well, or might also be able to get away by connecting that to ground if you are hard pressed to simplify wiring (depending on the display).

To get good performance out of the displays, you will drive the displays far out above the rated speed specs (the rated specs yield about ~10fps depending on display). Due to this, you will need to explicitly configure the target speed you want to drive the display at, because due to manufacturing variances each display copy reaches a different maximum speed. There is no "default speed" that fbcp-ili9341 would use. Setting the speed is done via the option

-DSPI_BUS_CLOCK_DIVISOR=even_number: Sets the clock divisor number which along with the Pi core_freq= option in /boot/config.txt specifies the overall speed that the display SPI communication bus is driven at. SPI_frequency = core_freq/divisor. SPI_BUS_CLOCK_DIVISOR must be an even number. Default Pi 3B and Zero W core_freq is 400MHz, and generally a value -DSPI_BUS_CLOCK_DIVISOR=6 seems to be the best that a ILI9341 display can do. Try a larger value if the display shows corrupt output, or a smaller value to get higher bandwidth. See ili9341.h and waveshare35b.h for data points on tuning the maximum SPI performance. Safe initial value could be something like -DSPI_BUS_CLOCK_DIVISOR=30.

-DSINGLE_CORE_BOARD=ON: Pass this option if you are running on a Pi that has only one hardware thread (Pi Model A, Pi Model B, Compute Module 1, Pi Zero/Zero W). If not present, autodetected.

-DBACKLIGHT_CONTROL=ON: If set, enables fbcp-ili9341 to control the display backlight in the given backlight pin. The display will go to sleep after a period of inactivity on the screen. If not, backlight is not touched.

-DSTATISTICS=number: Specifies the level of overlay statistics to show on screen. 0: disabled, 1: enabled, 2: enabled, and show frame rate interval graph as well. Default value is 1 (enabled).

-DDISPLAY_SWAP_BGR=ON: If this option is passed, red and blue color channels are reversed (RGB<->BGR) swap. Some displays have an opposite color panel subpixel layout that the display controller does not automatically account for, so define this if blue and red are mixed up.

-DLOW_BATTERY_PIN=: Specifies a GPIO pin that can be polled to get the battery state. By default, when this is set, a low battery icon will be displayed if the pin is pulled low (see config.h for ways in which this can be tweaked).

In addition to the above CMake directives, there are various defines scattered around the codebase, mostly in config.h, that control different runtime options. Edit those directly to further tune the behavior of the program. In particular, after you have finished with the setup, you may want to build with -DSTATISTICS=0 option in CMake configuration line.

Here is a full example of what to type to build and run, if you have the Adafruit 2.8" 320x240 TFT w/ Touch screen for Raspberry Pi with ILI9341 controller:

If the size of the default HDMI output /dev/fb0 framebuffer differs from the resolution of the display, the source video size will by default be rescaled to fit to the size of the SPI display. fbcp-ili9341 will manage setting up this rescaling if needed, and it will be done by the GPU, so performance should not be impacted too much. However if the resolutions do not match, small text will probably appear illegible. The resizing will be done in aspect ratio preserving manner, so if the aspect ratios do not match, either horizontal or vertical black borders will appear on the display. If you do not use the HDMI output at all, it is probably best to configure the HDMI output to match the SPI display size so that rescaling will not be needed. This can be done by setting the following lines in /boot/config.txt:

The refresh speed of the display is dictated by the clock speed of the SPI bus that the display is connected to. Due to the way the BCM2835 chip on Raspberry Pi works, there does not exist a simple speed=xxx Mhz option that could be set to define the bus speed. Instead, the SPI bus speed is derived from two separate parameters: the core frequency of the BCM2835 SoC in general (core_freq in /boot/config.txt), and the SPI peripheral CDIV (Clock DIVider) setting. Together, the resulting SPI bus speed is then calculated with the formula SPI_speed=core_freq/CDIV.

Adjust the CDIV value by passing the directive -DSPI_BUS_CLOCK_DIVISOR=number in CMake command line. Possible values are even numbers 2, 4, 6, 8, .... Note that since CDIV appears in the denominator in the formula for SPI_speed, smaller values result in higher bus speeds, whereas higher values make the display go slower. Initially when you don"t know how fast your display can run, try starting with a safe high setting, such as -DSPI_BUS_CLOCK_DIVISOR=30, and work your way to smaller numbers to find the maximum speed the display can cope with. See the table at the end of the README for specific observed maximum bus speeds for different displays.

Perhaps a bit counterintuitively, underclock the core. Setting a smaller core frequency than the default turbo 400MHz can enable using a smaller clock divider to get a higher resulting SPI bus speed. For example, if with default core_freq=400 SPI CDIV=8 works (resulting in SPI bus speed 400MHz/8=50MHz), but CDIV=6 does not (400MHz/6=66.67MHz was too much), you can try lowering core_freq=360 and set CDIV=6 to get an effective SPI bus speed of 360MHz/6=60MHz, a middle ground between the two that might perhaps work. Balancing core_freq= and CDIV options allows one to find the maximum SPI bus speed up to the last few kHz that the display controller can tolerate. One can also try the opposite direction and overclock, but that does then of course have all the issues that come along when overclocking. Underclocking does have the drawback that it makes the Pi run slower overall, so this is certainly a tradeoff.

The main option to control CPU usage vs performance aspect is the option #define ALL_TASKS_SHOULD_DMA in config.h. Enabling this option will greatly reduce CPU usage. If this option is disabled, SPI bus utilization is maximized but CPU usage can be up to 80%-120%. When this option is enabled, CPU usage is generally up to around 15%-30%. Maximal CPU usage occurs when watching a video, or playing a fast moving game. If nothing is changing on the screen, CPU consumption of the driver should go down very close to 0-5%. By default #define ALL_TASKS_SHOULD_DMA is enabled for Pi Zero, but disabled for Pi 3B.

If your SPI display bus is able to run really fast in comparison to the size of the display and the amount of content changing on the screen, you can try enabling #define UPDATE_FRAMES_IN_SINGLE_RECTANGULAR_DIFF option in config.h to reduce CPU usage at the expense of increasing the number of bytes sent over the bus. This has been observed to have a big effect on Pi Zero, so is worth checking out especially there.

A pleasing aspect of fbcp-ili9341 is that it introduces very little latency overhead: on a 119Hz refreshing ILI9341 display, fbcp-ili9341 gets pixels as response from GPIO input to screen in well less than 16.66 msecs time. I only have a 120fps recording camera, so can"t easily measure delays shorter than that, but rough statistical estimate of slow motion video footage suggests this delay could be as low as 2-3 msecs, dominated by the ~8.4msecs panel refresh rate of the ILI9341.

This does not mean that overall input to display latency in games would be so immediate. Briefly testing a NES emulated game in Retropie suggests a total latency of about 60-80 msecs. This latency is caused by the NES game emulator overhead and extra latency added by Linux, DispmanX and GPU rendering, and GPU framebuffer snapshotting. (If you ran fbcp-ili9341 as a static library bypassing DispmanX and the GPU stack, directly linking your GPIO input and application logic into fbcp-ili9341, you would be able to get down to this few msecs of overall latency, like shown in the above GPIO input video)

Unfortunately a limitation of SPI connected displays is that the VSYNC line signal is not available on the display controllers when they are running in SPI mode, so it is not possible to do vsync locked updates even if the SPI bus bandwidth on the display was fast enough. For example, the 4 ILI9341 displays I have can all be run faster than 75MHz so SPI bus bandwidth-wise all of them would be able to update a full frame in less than a vsync interval, but it is not possible to synchronize the updates to vsync since the display controllers do not report it. (If you do know of a display that does actually expose a vsync clock signal even in SPI mode, you can try implementing support to locking on to it)

Another option that is known to affect how the tearing artifact looks like is the internal panel refresh rate. For ILI9341 displays this refresh rate can be adjusted in ili9341.h, and this can be set to range between ILI9341_FRAMERATE_61_HZ and ILI9341_FRAMERATE_119_HZ (default). Slower refresh rates produce less tearing, but have higher input-to-display latency, whereas higher refresh rates will result in the opposite. Again visually the resulting effect is a bit subjective.

To get tearing free updates, you should use a DPI display, or a good quality HDMI display. Beware that cheap small 3.5" HDMI displays such as KeDei do also tear - that is, even if they are controlled via HDMI, they don"t actually seem to implement VSYNC timed internal operation.

Having no vsync is not all bad though, since with the lack of vsync, SPI displays have the opportunity to obtain smoother animation on content that is not updating at 60Hz. It is possible that content on the SPI display will stutter even less than what DPI or HDMI displays on the Pi can currently provide (although I have not been able to test this in detail, except for the KeDei case above).

The main option that affects smoothness of display updates is the #define USE_GPU_VSYNC line in config.h. If this is enabled, then the internal Pi GPU HDMI vsync clock is used to drive frames onto the display. The Pi GPU clock runs at a fixed rate that is independent of the content. This rate can be discovered by running tvservice -s on the Pi console, and is usually 59Hz or 60Hz. If your application renders at this rate, animation will look smooth, but if not, there will be stuttering. For example playing a PAL NES game that updates at 50Hz with HDMI clock set at 60Hz will cause bad microstuttering in video output if #define USE_GPU_VSYNC is enabled.

If USE_GPU_VSYNC is disabled, then a busy spinning GPU frame snapshotting thread is used to drive the updates. This will produce smoother animation in content that does not maintain a fixed 60Hz rate. Especially in OpenTyrian, a game that renders at a fixed 36fps and has slowly scrolling scenery, the stuttering caused by USE_GPU_VSYNC is particularly visible. Running on Pi 3B without USE_GPU_VSYNC enabled produces visually smoother looking scrolling on an Adafruit 2.8" ILI9341 PiTFT set to update at 119Hz, compared to enabling USE_GPU_VSYNC on the same setup. Without USE_GPU_VSYNC, the dedicated frame polling loop thread "finds" the 36Hz update rate of the game, and then pushes pixels to the display at this exact rate. This works nicely since SPI displays disregard vsync - the result is that frames are pushed out to the SPI display immediately as they become available, instead of pulling them at a fixed 60Hz rate like HDMI does.

A drawback is that this kind of polling consumes more CPU time than the vsync option. The extra overhead is around +34% of CPU usage compared to the vsync method. It also requires using a background thread, and because of this, it is not feasible to be used on a single core Pi Zero. If this polling was unnecessary, this mode would also work on a Pi Zero, and without the added +34% CPU overhead on Pi 3B. See the Known Issues section below for more details.

There are two other main options that affect frame delivery timings, #define SELF_SYNCHRONIZE_TO_GPU_VSYNC_PRODUCED_NEW_FRAMES and #define SAVE_BATTERY_BY_PREDICTING_FRAME_ARRIVAL_TIMES. Check out the video fbcp-ili9341 frame delivery smoothness test on Pi 3B and Adafruit ILI9341 at 119Hz for a detailed side by side comparison of these different modes. The conclusions drawn from the four tested scenarios in the video are:

The codebase captures screen framebuffers by snapshotting via the VideoCore vc_dispmanx_snapshot() API, and the obtained pixels are then routed on to the SPI-based display. This kind of polling is performed, since there does not exist an event-based mechanism to get new frames from the GPU as they are produced. The result is inefficient and can easily cause stuttering, since different applications produce frames at different paces. Ideally the code would ask the VideoCore API to receive finished frames in callback notifications immediately after they are rendered, but this kind of functionality does not exist in the current GPU driver stack. In the absence of such event delivery mechanism, the code has to resort to polling snapshots of the display framebuffer using carefully timed heuristics to balance between keeping latency and stuttering low, while not causing excessive power consumption. These heuristics keep continuously guessing the update rate of the animation on screen, and they have been tuned to ensure that CPU usage goes down to 0% when there is no detected activity on screen, but it is certainly not perfect. This GPU limitation is discussed at raspberrypi/userland#440. If you"d like to see fbcp-ili9341 operation reduce latency, stuttering and power consumption, please throw a (kind!) comment or a thumbs up emoji in that bug thread to share that you care about this, and perhaps Raspberry Pi engineers might pick the improvement up on the development roadmap. If this issue is resolved, all of the #define USE_GPU_VSYNC, #define SAVE_BATTERY_BY_PREDICTING_FRAME_ARRIVAL_TIMES and #define SELF_SYNCHRONIZE_TO_GPU_VSYNC_PRODUCED_NEW_FRAMES hacks from the previous section could be deleted from the driver, hopefully leading to a best of all worlds scenario without drawbacks.

Currently if one resizes the video frame size at runtime, this causes DispmanX API to go sideways. See raspberrypi/userland#461 for more information. Best workaround is to set the desired screen resolution in /boot/config.txt and configure all applications to never change that at runtime.

The speed of the SPI bus is linked to the BCM2835 core frequency. This frequency is at 250MHz by default (on e.g. Pi Zero, 3B and 3B+), and under CPU load, the core turbos up to 400MHz. This turboing directly scales up the SPI bus speed by 400/250=+60% as well. Therefore when choosing the SPI CDIV value to use, one has to pick one that works for both idle and turbo clock speeds. Conversely, the BCM core reverts to non-turbo speed when there is only light CPU load active, and this slows down the display, so if an application is graphically intensive but light on CPU, the SPI display bus does not get a chance to run at maximum speeds. A way to work around this is to force the BCM core to always stay in its turbo state with force_turbo=1 option in /boot/config.txt, but this has an unfortunate effect of causing the ARM CPU to always run in turbo speed as well, consuming excessive amounts of power. At the time of writing, there does not yet exist a good solution to have both power saving and good performance. This limitation is being discussed in more detail at raspberrypi/firmware#992.

By default fbcp-ili9341 builds with a statistics overlay enabled. See the video fbcp-ili9341 ported to ILI9486 WaveShare 3.5" (B) SpotPear 320x480 SPI display to find details on what each field means. Build with CMake option -DSTATISTICS=0 to disable displaying the statistics. You can also try building with CMake option -DSTATISTICS=2 to show a more detailed frame delivery timings histogram view, see screenshot and video above.

The fbcp part in the name means framebuffer copy; specifically for the ILI9341 controller. fbcp-ili9341 is not actually a framebuffer copying driver, it does not create a secondary framebuffer that it would copy bytes across to from the primary framebuffer. It is also no longer a driver only for the ILI9341 controller. A more appropriate name might be userland-raspi-spi-display-driver or something like that, but the original name stuck.

Yes, it does, although not quite as well as on Pi 3B. If you"d like it to run better on a Pi Zero, leave a thumbs up at raspberrypi/userland#440 - hard problems are difficult to justify prioritizing unless it is known that many people care about them.

Edit the file config.h and comment out the line #define DISPLAY_OUTPUT_LANDSCAPE. This will make the display output in portrait mode, effectively rotating it by 90 degrees. Note that this only affects the pixel memory reading mode of the display. It is not possible to change the panel scan order to run between landscape and portrait, the SPI displays typically always scan in portrait mode. The result is that it will change the panel vsync tearing mode from "straight line tearing" over to "diagonal tearing" (see the section About Tearing above).

If you do not want to have diagonal tearing, but would prefer straight line tearing, then additionally enable the option #define DISPLAY_FLIP_ORIENTATION_IN_SOFTWARE in config.h. That will restore straight line tearing, but it will also increase overall CPU consumption.

Note that the setting DISPLAY_ROTATE_180_DEGREES only affects the pixel memory reading mode of the display. It is not possible to flip the panel scan to run inverted by 180 degrees. This means that adjusting these settings will also have effects of changing the visual appearance of the vsync tearing artifact. If you have the ability to mount the display 180 degrees around in your project, it is recommended to do that instead of using the DISPLAY_ROTATE_180_DEGREES option.

Edit the file config.h in a text editor (a command line one such as pico, vim, nano, or SSH map the drive to your host), and find the appropriate line in the file. Add comment lines // in front of that text to disable the option, or remove the // characters to enable it.

If fbcp-ili9341 does not support your display controller, you will have to write support for it. fbcp-ili9341 does not have a "generic SPI TFT driver routine" that might work across multiple devices, but needs specific code for each. If you have the spec sheet available, you can ask for advice, but please do not request to add support to a display controller "blind", that is not possible.

Perhaps. This is a more recent experimental feature that may not be as stable, and there are some limitations, but 3-wire ("9-bit") SPI display support is now available. If you have a 3-wire SPI display, i.e. one that does not have a Data/Control (DC) GPIO pin to connect, configure it via CMake with directive -DGPIO_TFT_DATA_CONTROL=-1 to tell fbcp-ili9341 that it should be driving the display with 3-wire protocol.

The performance option ALL_TASKS_SHOULD_DMA is currently not supported, there is an issue with DMA chaining that prevents this from being enabled. As result, CPU usage on 3-wire displays will be slightly higher than on 4-wire displays.

The performance option OFFLOAD_PIXEL_COPY_TO_DMA_CPP is currently not supported. As a result, 3-wire displays may not work that well on single core Pis like Pi Zero.

Displays that have a 16-bit wide command word, such as ILI9486, do not currently work in 3-wire ("17-bit") mode. (But ILI9486L has 8-bit command word, so that does work)

The one thing that fbcp-ili9341 stays clear off is that it does not program the non-volatile memory areas of any of the displays. Therefore a hard power off on a display should clear all performed initialization and reset the display to its initial state at next power on.

Yes, fbcp-ili9341 shows the output of the HDMI display on the SPI screen, and both can be attached at the same time. A HDMI display does not have to be connected however, although fbcp-ili9341 operation will still be affected by whatever HDMI display mode is configured. Check out tvservice -s on the command line to check what the current DispmanX HDMI output mode is.

At the moment fbcp-ili9341 has been developed to only display the contents of the main DispmanX GPU framebuffer over to the SPI display. That is, the SPI display will show the same picture as the HDMI output does. There is no technical restriction that requires this though, so if you know C/C++ well, it should be a manageable project to turn fbcp-ili9341 to operate as an offscreen display library to show a completely separate (non-GPU-accelerated) image than what the main HDMI display outputs. For example you could have two different outputs, e.g. a HUD overlay, a dashboard for network statistics, weather, temps, etc. showing on the SPI while having the main Raspberry Pi desktop on the HDMI.

In this kind of mode, you would probably strip the DispmanX bits out of fbcp-ili9341, and recast it as a static library that you would link to in your drawing application, and instead of snapshotting frames, you can then programmatically write to a framebuffer in memory from your C/C++ code.

double check that the display controller is really what you expected. Trying to drive with the display with wrong initialization code usually results in the display not reacting, and the screen stays white,

shut down and physically power off the Pi and the display in between multiple tests. Driving a display with a wrong initialization routine may put it in a bad state that needs a physical power off for it to reset,

This suggests that the power line or the backlight line might not be properly connected. Or if the backlight connects to a GPIO pin on the Pi (and not a voltage pin), then it may be that the pin is not in correct state for the backlight to turn on. Most of the LCD TFT displays I have immediately light up their backlight when they receive power. The Tontec one has a backlight GPIO pin that boots up high but must be pulled low to activate the backlight. OLED displays on the other hand seem to stay all black even after they do get power, while waiting for their initialization to be performed, so for OLEDs it may be normal for nothing to show up on the screen immediately after boot.

fbcp-ili9341 runs a clear screen command at low speed as first thing after init, so if that goes through, it is a good sign. Try increasing -DSPI_BUS_CLOCK_DIVISOR= CMake option to a higher number to see if the display driving rate was too fast. Or try disabling DMA with -DUSE_DMA_TRANSFERS=OFF to see if this might be a DMA conflict.

This suggests same as above, increase SPI bus divisor or troubleshoot disabling DMA. If DMA is detected to be the culprit, try changing up the DMA channels. Double check that /boot/config.txt does not have any dtoverlays regarding other SPI display drivers or touch screen controllers, and that it does NOT have a dtparam=spi=on line in it - fbcp-ili9341 does not use the Linux kernel SPI driver.

Check that the Pi is powered off of a power supply that can keep up with the voltage, and the low voltage icon is not showing up. (remove any avoid_warnings=1/2 directive from /boot/config.txt if that was used to get rid of warnings overlay, to check that voltage is good) It has been observed that if there is not enough power supplied, the display can be the first to starve, while the Pi might keep on running fine. Try removing turbo settings or lowering the clock speed if you have overclocked to verify that the display crash is not power usage related.

If the colors looks off in some other fashion, it is possible that the display is just being driven at a too high SPI bus speed, in which case try making the display run slower by choosing a higher -DSPI_BUS_CLOCK_DIVISOR= option to CMake. Especially on ILI9486 displays it has been observed that the colors on the display can become distorted if the display is run too fast beyond its maximum capability.

As the number of supported displays, Raspberry Pi device models, Raspbian/Retropie/Lakka OS versions, accompanied C++ compiler versions and fbcp-ili9341 build options have grown in number, there is a combinatorial explosion of all possible build modes that one can put the codebase through, so it is not easy to keep every possible combo tested all the time. Something may have regressed or gotten outdated. Stay calm, and report a bug.

You can also try looking through the commit history to find changes related to your configuration combo, to see if there"s a mention of a known good commit in time that should work for your case. If you get an odd compiler error on cmake or make lines, those will usually be very easy to fix, as they are most of the time a result of some configurational oversight.

First, make sure the display is a 4-wire SPI and not a 3-wire one. A display is 4-wire SPI if it has a Data/Control (DC) GPIO line that needs connecting. Sometimes the D/C pin is labeled RS (Register Select). Support for 3-wire SPI displays does exist, but it is experimental and not nearly as well tested as 4-wire displays.

Second is the consideration about display speed. Below is a performance chart of the different displays I have tested. Note that these are sample sizes of one, I don"t know how much sample variance there exists. Also I don"t know if it is likely that there exists big differences between displays with same controller from different manufacturers. At least the different ILI9341 displays that I have are all quite consistent on performance, whether they are from Adafruit or WaveShare or from BuyDisplay.com.

In this list, Rated SPI Bus Speed is the maximum clock speed that the display controller is rated to run at. The Obtained Bus Speed column lists the fastest SPI bus speed that was achieved in practice, and the core_freq BCM Core speed and SPI Clock Divider CDIV setting that was used to achieve that rate. Note how most display controllers can generally be driven much faster than what they are officially rated at in their spec sheets.

The Frame Rate column shows the worst case frame rate when full screen updates are being performed. This occurs for example when watching fullscreen video (that is not a flat colored cartoon). Because fbcp-ili9341 only sends over the pixels that have changed, displays such as HX8357D and ILI9486 can still be used to play many games at 60fps. Retro games work especially well.

Search around, or ask the manufacturer of the display what the maximum SPI bus speed is for the device. This is the most important aspect to getting good frame rates, but unfortunately most web links never state the SPI speed rating, or they state it ridiculously low like in the spec sheets. Try and buy to see, or ask in some community forums from people who already have a particular display to find out what SPI bus speed it can achieve.

One might think that since Pi Zero is slower than a Pi 3, the SPI bus speed might not matter as much when running on a Pi Zero, but the effect is rather the opposite. To get good framerates on a Pi Zero, it should be paired with a display with as high SPI bus speed capability as possible. This is because the higher the SPI bus speed is, the more autonomously a DMA controller can drive it without CPU intervention. For the same reason, the interlacing technique does not (currently at least) perform well on a Pi Zero, so it is disabled there by default. ILI9341s run well on Pi Zero, ILI9486 on the other hand is quite difficult to combine with a Pi Zero.

Ultimately, it should be noted that parallel displays (DPI) are the proper method for getting fast framerates easily. SPI displays should only be preferred if display form factor is important and a desired product might only exist as SPI and not as DPI, or the number of GPIO pins that are available on the Pi is scarce that sacrificing dozens of pins to RGB data is not feasible.

Displays are generally manufactured to utilize one specific interfacing method, with the exception that some displays have a both I²C and SPI modes that can be configured via soldering.

Port fbcp-ili9341 to work as a static code library that one can link to another application for CPU-based drawing directly to display, bypassing inefficiencies and latency of the general purpose Linux DispmanX/graphics stack.

Improve existing display initialization routines with options to control e.g. gamma curves, color saturation, driving voltages, refresh rates or other potentially useful features that the display controller protocols expose.

Implement a kernel module that enables userland programs to allocate DMA channels, which fbcp-ili9341 could use to amicably reserve its own DMA channels without danger of conflicting.

Optimize away unnecessary zero padding that 3-wire communication currently incurs, by keeping a queue of leftover untransmitted partial bits of a byte, and piggybacking them onto the next transfer that comes in.

Port the high performance DMA-based SPI communication technique from fbcp-ili9341 over to another project that uses the SPI bus for something else, for close to 100% saturation of the SPI bus in the project.

Optimize ALL_TASKS_SHOULD_DMA mode to be always superior in performance and CPU usage so that the non-ALL_TASKS_SHOULD_DMA path can be dropped from the codebase. (probably requires the above chaining to function efficiently)

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

The Arduino family of devices is features rich and offers many capabilities. The ability to interface to external devices readily is very enticing, although the Arduino has a limited number of input/output options. Adding an external display would typically require several of the limited I/O pins. Using an I2C interface, only two connections for an LCD character display are possible with stunning professional results. We offer both a 4 x 20 LCD.

The character LCD is ideal for displaying text and numbers and special characters. LCDs incorporate a small add-on circuit (backpack) mounted on the back of the LCD module. The module features a controller chip handling I2C communications and an adjustable potentiometer for changing the intensity of the LED backlight. An I2C LCD advantage is that wiring is straightforward, requiring only two data pins to control the LCD.

A standard LCD requires over ten connections, which can be a problem if your Arduino does not have many GPIO pins available. If you happen to have an LCD without an I2C interface incorporated into the design, these can be easily

The LCD displays each character through a matrix grid of 5×8 pixels. These pixels can display standard text, numbers, or special characters and can also be programmed to display custom characters easily.

Connecting the Arduino UNO to the I2C interface of the LCD requires only four connections. The connections include two for power and two for data. The chart below shows the connections needed.

The I2C LCD interface is compatible across much of the Arduino family. The pin functions remain the same, but the labeling of those pins might be different.

Located on the back of the LCD screen is the I2C interface board, and on the interface is an adjustable potentiometer. This adjustment is made with a small screwdriver. You will adjust the potentiometer until a series of rectangles appear – this will allow you to see your programming results.

The Arduino module and editor do not know how to communicate with the I2C interface on the LCD. The parameter to enable the Arduino to send commands to the LCD are in separately downloaded LiquidCrystal_I2C library.

Before installing LiquidCrystal_I2C, remove any other libraries that may reside in the Arduino IDE with the same LiquidCrystal_I2C name. Doing this will ensure that only the known good library is in use. LiquidCrystal_I2C works in combination with the preinstalled Wire.h library in the Arduino editor.

Several examples and code are included in the Library installation, which can provide some reference and programming examples. You can use these example sketches as a basis for developing your own code for the LCD display module.

The I2c address can be changed by shorting the address solder pads on the I2C module. You will need to know the actual address of the LCD before you can start using it.

Once you have the LCD connected and have determined the I2C address, you can proceed to write code to display on the screen. The code segment below is a complete sketch ready for downloading to your Arduino.

The code assumes the I2C address of the LCD screen is at 0x27 and can be adjusted on the LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x27,16,2); as required.

This function turns off any characters displayed to the LCD. The text will not be cleared from the LCD memory; rather, it is turned off. The LCD will show the screen again when display() is executed.

Scrolling text if you want to print more than 16 or 20 characters in one line then the scrolling text function is convenient. First, the substring with the maximum of characters per line is printed, moving the start column from right to left on the LCD screen. Then the first character is dropped, and the next character is displayed to the substring. This process repeats until the full string has been displayed on the screen.

The LCD driver backpack has an exciting additional feature allowing you to create custom characters (glyph) for use on the screen. Your custom characters work with both the 16×2 and 20×4 LCD units.

To aid in creating your custom characters, there are a number of useful tools available on Internet. Here is a LCD Custom Character Generator which we have used.

Waveshare released 2 LCD HAT for RPi Zero, both have a tiny square LCD. The newer version have a 240 x 240 1.3" IPS LCD. It is 261 PPI and within the apple defined retina display range (218 - 458 PPI). This resolution is capable to emulate many retro game console in the CRT TV age, e.g. NES at 256 x 240 resolution, we can cut 8 pixels from both left and right overscan area and make it become 240 x 240.

To closely fit for the Waveshare 1.3" LCD HAT, it require a 8 mm tall 2 x 20 pins header. But I cannot buy one with 8 mm tall, so I will modify from a 12 mm tall pin header.

The interior size between RPi and LCD HAT can fit for a 5 mm x 23 mm x 45 mm battery, any LiPo battery with protection circuit that within this dimension should be ok.

Waveshare LCD HAT use low profile female pin header, it can make the product more slim. But we need a corresponding low profile male pin header at RPi Zero to make it. The male pin header should be 8 mm tall, but I cannot find on the web. So patch it from a 12 mm male pin header.

We need further config after RetroPie boot, before that, we need to enable DWC2 USB controller to make network connection between computer and Pi Zero.

Edit the codlin.txt in micro SD, insert "modules-load=dwc2,g_ether" after "rootwait" keyword. The result should be something like that:dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=PARTUUID=14a75fe9-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait modules-load=dwc2,g_ether quiet loglevel=3 consoleblank=0 plymouth.enable=0 quiet init=/usr/lib/raspi-config/init_resize.sh

Find the "static const int mk_arcade_gpio_maps[]" row and update to HAT button mapping:static const int mk_arcade_gpio_maps[] = {6,19,5,26,13,21,16,20,0,0,0,0};

Fine tune for 1.3" LCD: C Configuration / Tools -> 805 configedit -> 1 -> 0 -> 2 Render Resolution -> O Video output resolution -> OK -> Cancel -> Cancel -> Cancel

The LCD HAT have 3 buttons and 1 extra push button in the cross button, it can map to the retro game console that only have 4 buttons (select, start, A and B). The highest resolution for this type of game console should be NES, it have 256 x 240 resolution. It can just fit for the 240 x 240 LCD display if simply crop the horizontal overscan area.

sorry for all the questions but could you please tell me what pins on the waveshare board i should solder because i dont know how you numbered the pins and what their functions are

for some reason my screen stays blank and it seems to output to hdmi (my tv cant handle the resolution though. i don"t see anything but get a low res warning)

got it to work by adding "fbcp &" to /etc/rc.local above the word “exit” at the end of the file. but the display looks weird. is that a misconfiguration or is the display broken?

i could fix it. according to https://www.waveshare.com/w/upload/6/6b/1.3inch_lcd_hat_user_manual_en.pdf i did edit the /etc/modprobe.d/fbtft.conf with speed=40000000 instead of 125000000 looking good now0

Nice work. I followed your instructions but for example the game 1942 I cannot see to complete screen, there are black bars at the sides. If I put "rotate=1" in "config.txt" I get image complete (like your video) but it is rotated 90º. How can do it to get a complete image wihtout "rotate=1"?

Trouble is I can"t find the charging board you used and the ones that are available are nearly twice thed size and have a usb port.... Thats why I asked you what you used!0

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.