wiring_esp32.md

Heltec E-ink Modules

Wiring: ESP32

✅ ESP32 uses 3.3V logic. It can connect directly to the display.

Display	ESP32
VCC	3.3V
GND	GND
D/C	GPIO 2
SDI	GPIO 23 (VSPI MOSI)
CS	GPIO 4
CLK	GPIO 18 (VSPI SCK)
BUSY	GPIO 5

All pins can be changed, using an extended constructor:

DISPLAY_CLASS(DC_PIN, CS_PIN, BUSY_PIN, SDI_PIN, CLK_PIN); 

(Optional) Suggested additional wiring, for power saving

void setup() {
    // GPIO 15, PNP transistor
    display.useCustomPowerSwitch(15, PNP);

    //Later, when required:
    display.customPowerOff();
    display.customPowerOn();
}

(Optional) Additional wiring: MicroSD card module

✅ ESP32 uses 3.3V logic. It can connect directly to microSD module.

void setup() {
    // Set MicroSD CS pin
    display.useSD(22);
}

Micro SD Module	ESP32
VCC	3.3V
CS	GPIO 22
MOSI	GPIO 23 (VSPI MOSI)
SCK	GPIO 18 (VSPI SCK)
MISO	GPIO 19 (VSPI MISO)
GND	GND

Some pins are shared with the display.

MOSI and SCK pins can be changed in the display constructor (see above).

CS pin (card) must be set with useSD(cs). Any suitable GPIO pin may be used. Optionally, MISO may also be set, with useSD(cs, miso)