Part

TFT display, 240x320

A 2.4 inch color TFT over SPI, for games and gauges.

9 pins
In 5 projects
In 1 lesson

Drawn live by the editor's own code, at the size you see it.

At a glance

The TFT display, 240x320 in brief

What it is, and where it sits on the bench.

The ILI9341 drives the common 2.4 and 2.8 inch 240x320 color TFT breakouts, red boards with nine pins: VCC, GND, CS, RST, DC, SCK, MOSI, MISO and LED. It is SPI plus a DC line marking each byte command or data. On an Uno, SCK goes to 13, MOSI to 11 and MISO to 12, with CS and DC on any pins; on an ESP32 DevKit the SPI pins are 18, 23 and 19. VCC takes 5 V through a regulator, but the logic is 3.3 V, so a real module on a 5 V Uno wants a level shifter; an ESP32 drives it directly. Mokxi models the MIPI command set: CASET and PASET set a window, RAMWR streams RGB565 pixels into it, and the MV, MX and MY bits of MADCTL are all there is to setRotation(). The glass is the whole memory, so unlike the ST7735 and ST7789 there is no offset to get wrong. LED left low keeps the panel dark over a correct picture. Nothing is read back on MISO, the power and gamma tables are ignored, the 120 ms after SLPOUT is not enforced and there is no scrolling or backlight dimming.

Family: Displays
Pins: 9

A circuit built around it, running and explained: the TFT display simulator.

Pins

9 pins

Named as the editor names them, so a wire lands where you expect it.

Role

What it does

VCC

Input or output

Supply.

GND

Input or output

Ground.

Input

Chip select, active low.

RST

Input

Reset.

Input

Low for a command byte, high for its data or for pixels.

SCK

Input

SPI clock.

MOSI

Input

SPI data in.

MISO

Output

Present on the header, never driven; this model answers no register reads.

LED

Input or output

The backlight; pulling it low blanks the panel.

How to use it

How to use the ILI9341 2.4 inch TFT with an Arduino

Four signal wires and two straps, as in the Snake game beside this: CS to pin 10, DC to 9, SCK to 13 and MOSI to 11, with VCC, RST and LED all on 5 V. RST tied high just keeps the chip out of reset. LED is the backlight and a real pin: hold it low and the panel stays dark over a perfectly drawn picture. MISO can stay open, since nothing is read back.

Adafruit_ILI9341 compiles as it stands: construct it with the CS and DC pins, call begin() and setRotation(), then draw with the GFX calls. On an Uno every bit of every pixel is a pin change, so a full-screen fill takes a good part of a second. Snake repaints only the new head and the old tail each step, under three hundred pixels, which is what keeps it quick.

Part pin

Board pin

Pin 10

Pin 9

SCK

Pin 13

MOSI

Pin 11

RST

5 V

LED

5 V

VCC

5 V

GND

Pong, two buttons drives the same panel from an ESP32-C3 at 3.3 V, with CS on GPIO 6, DC on 7, SCK on 4 and MOSI on 5. Adafruit_ILI9341 compiles on every board here but the ATtiny85.

Arduino Uno: Snake on a 2.4 inch TFTlive0.000 s 0.00x

Hold the button

This is the simulator itself, running here. Click anything to open it in the editor.

Open this project in the editor Read the full tutorial

Text on the ILI9341 with the Adafruit calls

#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ILI9341.h>
Adafruit_ILI9341 tft(10, 9);  // CS, DC; RST strapped to 5 V
void setup() {
  tft.begin();
  tft.setRotation(1);
  tft.fillScreen(ILI9341_BLACK);
  tft.setTextColor(ILI9341_WHITE);
  tft.setCursor(10, 10);
  tft.print("Hello");
}
void loop() {}

How it is modeled

What is true about the TFT display, 240x320, here

In its help article’s own words: what the simulation gets right, and where it stops.

Modeled

MADCTL (command 0x36) is the whole of "rotation" on this controller: MV exchanges the two axes and MX/MY count the other way along them, and the frame handed to the display is always in the address counter's own coordinates, so the picture is upright whichever rotation the sketch chose. A module you rotate on the bench is a part you rotate on the canvas. CASET/PASET set the pixel window and RAMWR streams pixels into it, exactly as the datasheet has it.

Not modeled

BGR (a MADCTL bit some panels use for their color filter order) is accepted but has no effect: a pixel is always the RGB565 value that was written. The long init sequences every library sends (power control, gamma, frame rate, VCOM) are accepted and their parameters ignored, so a driver that sends a wrong or incomplete init gets a perfect picture here and whatever the panel feels like on the bench.

No timing at all on the bus. SCK has no maximum rate, CS has no setup or hold requirement, and a byte is latched the instant its eighth rising edge arrives. A real ILI9341 wants SWRESET followed by 5 ms of quiet and SLPOUT followed by 120 ms before it will take pixels; here both take effect immediately, so a driver that skips those waits works here and not on a real module. There is no frame rate, no tearing signal and no TE pin.

Also absent: vertical scrolling (0x33/0x37), partial mode, idle mode, tearing effect control, and gamma or VCOM having any visible effect. COLMOD accepts both 16-bit and 18-bit pixel formats, but a pixel is stored as RGB565 either way, so 18-bit mode loses the two extra bits per channel a real panel would keep. There is no backlight brightness. LED is on or off, not a PWM dimmer.

From ILI9341 color TFT, in full.

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