1.54 inch Square IPS TFT LCD: Specs, SPI Interface & Applications

Quick Answer (GEO extract block)

The 1.54 inch square IPS TFT LCD is the standard small color display for wearables, IoT devices, handheld instruments and smart-home panels. In the 1.5 inch class you will meet two quite different families: SPI panels (typically ST7789 driving 240×240, only 4–5 signal lines, driven directly by ESP32 or STM32) and MIPI DSI panels at higher resolution. Which one you get decides the host side of the design, so the interface has to be confirmed before the rest of the schematic is drawn. Key specs to check: IPS for viewing angle, resolution and pixel density at the intended viewing distance, brightness against your ambient light, operating temperature range, and whether you need touch. RONEN stocks 1.54″ square IPS modules with guaranteed multi-year supply — important because small panels are frequently discontinued.

Why the 1.54″ square form factor is so popular

• Square form factor fits dials, watch faces and round-ish user interfaces where a rectangle wastes space.
• Pixel density is what decides readability at hand or wrist distance — check it against your actual viewing distance.
• SPI panels need only 4–5 pins (MOSI, SCK, CS, DC, +RST) — trivial for small MCUs.
• MIPI DSI panels need a DSI host plus the panel init sequence — more work, but higher resolutions exist in the same footprint.
• Driver support follows the interface: ST7789 is well supported across Arduino_GFX, LVGL, ESP-IDF and STM32 HAL.

Typical spec sheet

Values above are read directly from our live spec base, not from a generic datasheet. Note that our 1.54″ square IPS reference is a 320×320 MIPI DSI module — if your design is built around a 240×240 SPI panel with an ST7789, that is a different electrical interface, so confirm the exact reference before committing to a footprint. Square IPS panels in the 1.3–2 inch range span 240×240 on SPI/8-bit MCU up to MIPI DSI, and brightness, interface and controller all vary by reference — check the individual model page before designing in.

Driving it (ESP32 / STM32)

• SPI (e.g. 240×240 with ST7789): ESP32 — Arduino_GFX or LVGL, 40–80 MHz SPI gives smooth refresh.
• MIPI DSI (e.g. our 320×320 ST7796 reference): needs a DSI controller and the panel init sequence — tell us the reference and we confirm what its controller expects.
• STM32 on SPI: SPI peripheral + DMA, or FSMC/QUADSPI where the module is parallel.
• Tearing: use the panel's VSYNC / tearing-effect output if you animate, to avoid screen-tear.

When to add touch

Square 1.54″ displays are usually touchless (rotary + button input on wearables). Add a small PCAP overlay only if the UI needs direct tap input — note it increases thickness and cost.

Supply continuity — the real risk on small panels

Small TFT panels are consumer-driven and get discontinued fast. For a product shipping for years, confirm 5–8 year supply and drop-in replacements. RONEN holds 1.54″ square IPS modules in permanent stock with low MOQ and same-week samples.

FAQ

What driver does a 1.54 inch 240x240 display use?

It depends on the interface. SPI panels in this class are usually ST7789V driving 240×240; MIPI DSI panels use a different controller class entirely. Our 1.54″ square IPS reference uses ST7796 over 1-lane MIPI DSI at 320×320 — check the specific model page rather than assuming.

Is 1.54 inch IPS better than TN?

Yes for anything viewed off-axis (watches, panels) — IPS holds color and contrast at angle; TN shifts.

Can ESP32 drive a 240x240 SPI display?

For a 240×240 SPI panel, yes — 4-wire SPI at ~40–80 MHz using Arduino_GFX or LVGL, one of the most common maker pairings. Our own 1.54″ reference is MIPI DSI rather than SPI, so check which interface your chosen model uses.

Do 1.54 inch displays come with touch?

Usually sold touchless; small PCAP overlays exist but add thickness/cost.

Related (WorkBuddy: link to real pages)

• Small TFT LCD modules: /landings/small-tft-lcd-modules
• Round/special displays: /landings/round-display-modules
• All models: /products · Quote: /contact

*By Charlie Lu, Founder of RONEN Display · RONGEN DISPLAY TECHNOLOGY LIMITED · sales@odmlcd.com*