stm32f429 tft lcd schematic price

Ahh yeah look at that! If you look closely, top right of the LCD, that’s obviously a flex connector for a resistive touch overlay (4 contacts running to the 4 sides of the LCD overlay).

A fair number of inexpensive baseboards/motherboards/accessories have also appeared for earlier versions. I hope Olimex puts out a couple nice STM32F429/427 boards.

I can see there is only a STLINK usb connector on board, so there is even no FS to expect. beside HS, I suppose does mean High Speed (480mbps). but HS anyway needs a separate physical layer USB chip for addition to STM32F4 chip and most likely this is chip is not present on this board anyway, because this is STM32F4+LCD+SDRAM demoboard and there is no need for USB at all.

I think Farnell’s 21€ will be accurate, as ST’s suggested USD price is $24. The placeholders for the STM32F429I-DISCO on element14 (a division of Farnell) and mouser show $42, which I think predates the later ST announcement. I think the ST announced $24 will hold, and the distributor prices will match that, as they have in the past.

I wouldn’t expect TI to hack profits from their calculator range, and HP have always been expensive, but ST could easily change their format to calculator-friendly. Clamshell design, LCD & battery in top half, CPU & keypad in bottom half, expansion pins to left / right of keypad makes a self contained unit.

HP Palm – Love the idea, hate the baguette (french bread loaf) layout. If I could get custom key covers, and surface-mount key switches, I’d be designing my own low-profile keypad to go with an LCD module. Top side keypad, bottom side CPU / RAM / USB / LCD driver / power regulation / expansion port.

Great find, thanks! Man, could they have buried the details on that guy any farther down into the document? I can’t help but feel like a quick pointer in the LCD section to “oh by the way there’s a touch screen, here’s how to talk to it” would have been a good idea.

It’s certainly useable in any other project where you have an onboard LCD controller. Especially any other project that happens to use a STM32F4. What difference would it have made if it had an external controller? Surely it’d have been on the same PCB. Were you hoping for a removeable SPI-interfaced module?

Look in the UM1670 user manual, paragraph 4.8: the tft includes an ILI9341 controller. The ILI9341 has it’s own graphics ram inside, it is not mapped into the STM32 address space. It is connected to the STM32 via a parallel bus. The ILI9341 and similar controllers are common on cheap chinese tfts. So it is no problem to source similar tfts for your final product after developing on the discovery board.

UM1670 in paragraph 4.8 also says that “The TFT LCD is a 2.41″ display of 262 K colors. Its definition is QVGA (240 x 320 dots) and is directly driven by the STM32F429ZIT6 using the RGB protocol”. ILI9341 has multiple modes of operation including direct RGB/HSYNC/VSYNC mode which bypasses internal GRAM. I don’t have the board yet but I assume display buffer is located in external SDRAM which is also on the board. The whole point of this kit is to show TFT and SDRAM interface in new STM32F4x9.

I’ve checked this discovery board firmware available from ST’s site (“STM32F429 discovery firmware package UM1662” number: STSW-STM32138, btw. finding it is a bit difficult – ST’s site is terrible):

Check again martin. Those lines have pullups to vdd and are connected to cpu pins. I have this board for some time and I can confirm that lcd is driven by lcd controller from cpu and frame buffer is in external dram which is also on the board.

STM32F429 has also LTDC driver for LCD like that, but this driver we will use later. For now we will use SPI for driving in serial mode and some other pins for controlling.

Remember: This library can also be used, if you are not using STM32F429 Discovery. It can be used in previous STM32F4 Discovery board. All pins can be changed in defines.h file which is included in project.

[Alberto di Bene] wanted to build an SDR for relatively low frequencies. Usually, you’d start with some front end to get the radio frequency signal down where you can work with it. But [Alberto] practically just fed an antenna into an STM32F429 Discovery board and did all the radio processing in the onboard ARM chip.

LVDS displays can vary a lot. LVDS displays are not governed by a set of well defined rules like MIPI DSI displays are. Therefore, it is up to the LCD manufacturer and the LVDS display driver IC manufacturer to use LVDS interface as they please, as long as they follow the physical interface and logic levels.

Based on this data, we can pick an LVDS transmitter IC. SN75LVDS84 from Texas Instruments is great for use with LCD displays that can be driven by an STM32.

IMPORTANT The touchscreen has a maximum frequency of 2MHz, which is probably slower than you want your TFT SPI clock. So in the routine that reads touch coordinates (ili9341_touch_pressed_t ili9341_touch_coordinate(ili9341_t *,uint16_t *,uint16_t *) in ILI9341/ili9341.c), make sure to adjust the lines that modify the SPI clock so that your baud rate is less than 2MHz before communicating with the touchscreen (e.g. MODIFY_REG(lcd->spi_hal->Instance->CR1, SPI_CR1_BR, SPI_BAUDRATEPRESCALER_128)), and then restored to whatever setting you use here immedaitely afterwards. See the comments in that source file for both locations.

If using the touchscreen, you will probably want to set Hardware NSSP=Disabled (slave/chip-select) in favor of a software implementation, since you will need one signal for the TFT and a separate one for the touchscreen. Any two unused GPIO digital output pins will work.

2.4” TFT LCD Module is one of the most common RGB color display modules. Therefore,  this module offer different applications from conventional display modules in features and usage. It offers multi-way communication protocols to the developers/designers. This TFT module is not popular only because of its color screen, it has a resistive touch on itself. The touch screen is accessible by microcontrollers and they are controllable by the users according to the requirements.  Additionally, it can display up to 240×320 pixels on a single screen. Even images can also show on the screen. It is mostly available in developing projects and low-cost devices only.

The pin configuration of the module is simple like other display devices. The only problem is the developers need to understand first which method is better to operate the TFT LCD display. Therefore, the TFT touch screen uses the diver to operate each pixel and the driver uses a small no of pins as input and makes it user friendly. The pin configuration is as follows:

These all pins from D0~D7 are the digital data input pins. It requires only when a developer needs to work with LCD using 8-bit data or using Assemble language. The Arduino library mostly uses the SPI pins.

The LCD screen is made up of three types of pixels at a single point. The LCD uses the two polarized layers to pass the layer but both layers are opposite in pattern to each other. The liquid crystals relate to anode and cathode which makes the liquid crystal change their angle which helps to change the angle of light. The change in angle allows the light to pass from the polarized layers. There is always a total combination of three colors of pixels which are known as RGB. The intensity of pixels is controllable and helps to manage each pixel. The change in intensity changes the angle of the crystals and which makes the output light according to the image or text requirement.

Each pixel in the LCD needs to control according to the requirement individually. There are a driver ILI9341 which can control each pixel with the small no of pins which we already discussed above. In LCD the driver also attached to the Arduino shield. The Arduino shield comes with simple input pins but the driver output pins which are the most important pin. These pins are the source and gate driver pins. The source pins are 720pin and the gate pins are 320pins. The driver has an internal GRAM that stores the data each time the microcontroller send to it. The data on the display screen always temporary and stay in the GRAM until it needs to show to the screen. The following block diagram shows the internal structure of the driver ILI9341:

The LCD is useable with Arduino but it depends on the library. The library is compatible with Arduino only and compatible with the attached shield. To use the library first attach the LCD on the Arduino UNO or attach it by connecting wires on the other Arduino. Here’s the Arduino Uno with TFT shield:

The above libraries will help but to use the LCD first describe the LCD pins attached to the Arduino. It is changeable with the requirement of the LCD use. There are other libraries which can perform different functions which the above library unable to perform. There is some no of pins that need to describe.

The initialize the LCD in the Arduino setup. To initialize the LCD always remember it could give some errors. To avoid errors, use the reset commands.

The following command will make the whole screen black because the use of white color on the screen won’t show the data on the screen. So always define the screen fill color to describe the screen. The usage of the image is only most of the time with images and text. Every function on the LCD needs to change from the display command only but the rest of the data will be the same on the LCD. The internal SD card solves the memory issue.

STM32F469/479 – 180 MHz CPU/225 DMIPS, up to 2 Mbytes of dual-bank Flash with SDRAM and QSPI interface, Chrom-ART Accelerator™, LCD-TFT controller and MPI-DSI interface