LCD 128x64 ST7920 (serial mode) with ESP32

Supply 5 V Bus SPI

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
GND	Ground	GND
VCC	Power	VIN	5 V: use VIN
V0	Not wired to the ESP32	—	Contrast. Many boards have a trimmer on the back instead
RS	SPI chip select	D5	Serial mode: chip select (CS), active HIGH
R/W	SPI MOSI	D23	Serial mode: data in (SID). A level shifter to 5 V makes it reliable
E	SPI clock	D18	Serial mode: clock (SCLK)
DB0	Not wired to the ESP32	—	Parallel mode only
DB1	Not wired to the ESP32	—	Parallel mode only
DB2	Not wired to the ESP32	—	Parallel mode only
DB3	Not wired to the ESP32	—	Parallel mode only
DB4	Not wired to the ESP32	—	Parallel mode only
DB5	Not wired to the ESP32	—	Parallel mode only
DB6	Not wired to the ESP32	—	Parallel mode only
DB7	Not wired to the ESP32	—	Parallel mode only
PSB	Ground	GND	LOW selects serial mode: connect to GND
NC	Not wired to the ESP32	—	Not connected
RST	Input (the ESP32 drives it)	D25	Reset, active LOW. Can also be tied HIGH
VOUT	Not wired to the ESP32	—	Contrast voltage output. Leave unconnected
BLA	Not wired to the ESP32	—	Backlight anode: to 5 V
BLK	Not wired to the ESP32	—	Backlight cathode: to GND

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

void setup() { pinMode(25, OUTPUT); }  // RST

void loop() {
  digitalWrite(25, HIGH);
  delay(500);
  digitalWrite(25, LOW);
  delay(500);
}

Sitronix ST7920 datasheet, Serial interface: CS (RS), SID (R/W), SCLK (E); PSB LOW selects serial

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.