ST7735S Interface Description

The ST7735S supports SPI and parallel interfaces, allowing flexible communication with microcontrollers for driving 262K-color TFT LCDs.OverviewThe 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 Interfaces1. 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 inputSDA/MOSI: Serial data inputCS: Chip select, active lowDC (Data/Command): Selects between command or data modeRESET: Hardware reset inputSPI 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 widthWR: Write strobeRD: Read strobeCS: Chip selectDC: Data/Command selectionRESET: Hardware resetParallel mode allows faster data transfer compared to SPI, suitable for high-refresh applications.Control SignalsRESET: 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 RAMThe 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.SummaryThe ST7735S provides flexible interfacing options for embedded systems:SPI for low-pin-count, slower-speed applicationsParallel interface for high-speed data transferIntegrated RAM and power circuits simplify display designControl 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 .