The ST7735S interface is

The ST7735S supports SPI and parallel interfaces, allowing flexible communication with microcontrollers for driving 262K-color TFT LCDs.

Overview

The ST7735S is a single-chip TFT LCD controller/driver designed for 128x160 or 132x162 pixel displays with 18-bit color depth . It integrates source and gate drivers, on-chip display RAM, and power supply circuits, enabling a compact display system with minimal external components . The chip can interface directly with microcontrollers via Serial Peripheral Interface (SPI) or parallel interfaces (8-bit, 9-bit, 16-bit, or 18-bit) depending on the application .

Communication Interfaces

1. SPI Interface (Serial Communication)

• The ST7735S supports standard SPI, which is commonly used in microcontroller projects for simplicity and fewer pins .
• Typical SPI pins include:
  • SCL/SCK: Serial clock input
  • SDA/MOSI: Serial data input
  • CS: Chip select, active low
  • DC (Data/Command): Selects between command or data mode
  • RESET: Hardware reset input
• SPI allows the microcontroller to send commands and pixel data serially, reducing wiring complexity. 2. Parallel Interface (8/9/16/18-bit)
• For higher-speed applications, the ST7735S can use a parallel interface.
• Parallel pins include:
  • DB0–DB7/DB0–DB17: Data bus lines depending on bit width
  • WR: Write strobe
  • RD: Read strobe
  • CS: Chip select
  • DC: Data/Command selection
  • RESET: Hardware reset
• Parallel mode allows faster data transfer compared to SPI, suitable for high-refresh applications.

Control Signals

• RESET: Resets the display controller to default state.
• CS (Chip Select): Enables communication with the microcontroller.
• DC (Data/Command): Determines whether the transmitted byte is a command or display data.
• WR/RD: Used in parallel mode to latch data into the display RAM or read from it.

Display Data RAM

• The ST7735S contains on-chip display RAM of 132 x 162 x 18 bits .
• Data can be written or read without an external operation clock, minimizing power consumption.
• Commands allow setting the column and row address window, after which pixel data can be streamed to update the display.

Summary

The ST7735S provides flexible interfacing options for embedded systems:

• SPI for low-pin-count, slower-speed applications
• Parallel interface for high-speed data transfer
• Integrated RAM and power circuits simplify display design
• Control signals (RESET, CS, DC, WR/RD) manage communication and data flow This versatility makes the ST7735S suitable for Arduino, ESP32, and other microcontroller-based projects requiring compact, full-color TFT displays .