AW9523 16-bit I/O expander and LED driver with ESP32

Supply 3.3-5 V Bus I2C I2C address 0x58 / 0x59 / 0x5A / 0x5B

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VIN	Power	3V3	2.5 to 5.5 V
GND	Ground	GND
SCL	I2C clock (SCL)	D22
SDA	I2C data (SDA)	D21
INT	Interrupt	D35	Interrupt output, optional
RST	Not wired to the ESP32	—	Reset, active LOW, pulled up. Leave unconnected
AD0	Not wired to the ESP32	—	Address bit, default LOW
AD1	Not wired to the ESP32	—	Address bit, default LOW
P0_0	Not wired to the ESP32	—	Expander I/O: to your LEDs or buttons, not to the ESP32
P0_1	Not wired to the ESP32	—
P0_2	Not wired to the ESP32	—
P0_3	Not wired to the ESP32	—
P0_4	Not wired to the ESP32	—
P0_5	Not wired to the ESP32	—
P0_6	Not wired to the ESP32	—
P0_7	Not wired to the ESP32	—
P1_0	Not wired to the ESP32	—
P1_1	Not wired to the ESP32	—
P1_2	Not wired to the ESP32	—
P1_3	Not wired to the ESP32	—
P1_4	Not wired to the ESP32	—
P1_5	Not wired to the ESP32	—
P1_6	Not wired to the ESP32	—
P1_7	Not wired to the ESP32	—

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

Check it is the real chip

Read register 0x10: a genuine part answers 0x23. BoardPilot does this automatically in “Debug a problem”.

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x58);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "AW9523 16-bit I/O expander and LED driver found at 0x58" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Awinic AW9523B datasheet, Address 10110 AD1 AD0 (0x58 to 0x5B); ID register 0x10 reads 0x23; constant-current LED mode
Adafruit AW9523 GPIO expander and LED driver guide, Pinouts. Check the silkscreen for the header order

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

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