In TFT LCD displays, the interface signal types include SPI, MCU, RGB, LVDS, MIPI, eDP, and HDMI. Among these, SPI, MCU, RGB, LVDS, and HDMI interfaces are widely used in the market. Different interface types have their specific characteristics.
LCD displays using MCU interfaces have faster refresh rates compared to those using SPI interfaces, and software control via MCU interfaces is also simpler. The advantages of MCU interfaces are obvious. However, they require more interface pin resources.
Under normal circumstances, the pin order of the TFT LCD screen interface definition is not fixed and varies depending on the client motherboard design. However, for LCD screens using MCU interface types, the key pins are essential. Different interface types require different pin functions, and the choice of interface type is not arbitrary; it must be selected based on the specifications of the different main chips.
2.8-inch MCU display
2.8-inch TFT MCU LCD
- Size: 2.8
- Resolution: 240×320 dots
- Viewing angle: 12 O'clock
- Interface type: MCU
- Driver chip: ST7789V
- Touch method: TBD
- Backlight brightness: 360 cd/m²
- Dimensions: 50.00 (W) * 69.20 (H) * 3.30 (T) mm
I. PIN Example
| NO. | symbol | Description |
| 1 | LEDK | BACKLIGHT CATHODE |
| 2 | LED-A | BACKLIGHT ANODE |
| 3 | GND | Grounds |
| 4 | VCC | POWER SUPPLY |
| 5 | IOVCC | I/O POWER SUPPLY |
| 6 | NC | NC |
| 7 | CS | Chip enable, Low-active. |
| 8 | RESET | Reset pin |
| 9 | RS | Data/Command register address. |
| 10 | WR | Write signal, rising-edge-trigger. |
| 11 | RD | Read signal, rising-edge-active. |
| 12-19 | DB7-DB0 | Data Bus |
| 20 | GND | Grounds |
II. Typical STM32/AVR/MCU Connection Examples (Replace pin names according to the actual MCU)
Display Pin → MCU pin / notes
CS → Any GPIO (active low). If there is only one peripheral, it can be directly pulled low to ground (but it is recommended to connect a GPIO for software control).
RESET → Any GPIO (pulled high by software after external reset)
RS (D/C/A0) → Any GPIO (distinguishes between instruction and data)
WR → Any GPIO (write pulse, note the rising edge sampling)
RD → Any GPIO (read pulse, used to read data when necessary)
DB0..DB7 → MCU's 8-bit parallel ports (it is recommended to place them in the same I/O port group for easy one-time write operations).
GND → MCU GND
IOVCC → MCU Vcc (logic)
VCC → Module main power supply
LED-A / LEDK → Backlight Driver / Constant Current Source
It is recommended to connect DB0–DB7 to the same group of ports (such as an 8-bit GPIO port of STM32). This way, the entire byte can be output by writing to the register at once, which is more efficient and has better timing.
III. Connection Example
Display -> STM32 example
DB0..DB7 -> PB0..PB7 (Write out in one go: GPIOB->ODR = value)
RS -> PA0
WR -> PA1
RD -> PA2
CS -> PA3
RESET -> PA4
IOVCC -> 3.3V
VCC -> 3.3V (or 5V per module)
GND -> GND
LED-A/K -> Backlight driver MOSFET / driver
- First, read the datasheet: determine VCC, IOVCC, voltage, and initialization commands.
- Connect DB0–DB7 to the same group of GPIOs (for easy whole-word writing).
- The backlight is controlled by a constant current driver or MOSFET + PWM.
- Properly handle level compatibility (use level shifters if the levels are different).
- Write a reliable reset + initialization sequence, strictly following the delays and commands in the datasheet.
IV. Initialization Code for TFT Display Screen
You can directly request the "driver initialization code" or "MCU demo code" from the sales engineer of Hongcai Technology Company.
