AW9523 GPIO Expansion Chip Driver Documentation

Overview

This document explains how to use the AW9523 driver module to achieve GPIO expansion functionality. This chip expands 16 bidirectional GPIO pins through the I2C interface, supports independent configuration of input/output modes, and has a level change interrupt detection function.

Main Features

• Supports 16 bidirectional GPIO pins expansion
• Allows independent configuration of each pin as input/output mode
• Supports high/low level control (output mode)
• Supports pin status reading (input mode)
• Built-in edge detection function (rising/falling edge)
• Real-time callback notification of interrupt status

Quick Start

1. Import Required Modules

from machine import I2C, ExtInt
from aw9523 import AW9523
from usr.common import create_thread
import utime

2. Initialize the sensors

# Create an instance of the I2C device (I2C1, standard mode) 
i2c_dev = I2C(I2C.I2C1, I2C.STANDARD_MODE)

# Define the interrupt callback function 
def int_callback(pin_data):
    pin, level = pin_data
    print("Pin {} has a level change! Current level: {}".format(pin, 'High' if level else 'Low')) 

# Initialize the AW9523 chip on the I2C0 bus (address 0x58, using pin 1 as the interrupt pin) 
expander = AW9523(
    i2c_bus=i2c_dev,
    int_pin = 1,                 # Interrupt pin number
    int_callback = int_callback  # Interrupt callback function 
    )

3. Configure GPIO pins

# Set pin 0 to output mode and set it to high level 
expander.pin(0, mode=0, value=1)

# Set pin 8 to input mode and enable interrupts 
expander.pin(8, mode=1, interrupt_enable=1)

# Set pin 9 to input mode and disable interrupts 
expander.pin(9, mode=1, interrupt_enable=0)

4. Read the pin status

# Read the current level state of pin 8 
level = expander.read(8)
print("Pin 8 current level: ".format('High' if level else 'Low')) 

# Read the status of all pins in batches 
all_pins_state = expander.gpio
print("All pin states: {}".format(bin(all_pins_state))) 

API Interface Description

AW9523(i2c_bus, int_pin=1, int_mode=0, int_callback=None, address=0x58)

Constructor, initializing the AW9523 chip

Parameter Description:

• i2c_bus: I2C bus instance
• int_pin: Interrupt detection pin number
• int_mode: Interrupt triggering mode
• int_callback: Interrupt callback function
• address: Device I2C address (0x58 or 0x5B)

pin(pin, mode=None, value=None, interrupt_enable=None)

Configure the specified pin parameters

Parameter Explanation:

• pin: Pin number (0-15)
• mode: Pin mode
  • 0: Output mode
  • 1: Input mode
• value: Output level value (valid in output mode)
  • 0: Low level
  • 1: High level
• interrupt_enable: Interrupt enable
  • 0: Disable interrupt
  • 1: Enable interrupt

read(pin)

Read the level status of the specified pin

Parameter Explanation:

• pin: Pin number (0-15)

• Return value:

  • 0: Low level
  • 1: High level

Attribute accessor

• mode: All pin mode status (16 bits)
• interrupt_enable: All pin interrupt enable status (16 bits)
• gpio: All pin level status (16 bits)

Application Example

Basic GPIO Expansion Application

i2c_dev = I2C(I2C.I2C1, I2C.STANDARD_MODE)
expander = AW9523(i2c_dev)

# Set pins 0 to 3 to output mode 
for i in range(4):
    expander.pin(i, mode=0, value=0)

# Set pins 8 to 11 to input mode 
for i in range(8, 12):
    expander.pin(i, mode=1, interrupt_enable=0)

while True:
    # Read the status of pins 8 to 1 
    for i in range(8, 12):
        state = expander.read(i)
        print("Pin {i} state: {state}".format(i, state))

    utime.sleep(1)

Interrupt detection application

def int_handler(pin_data):
    pin, level = pin_data
    print("Pin {} changed to {}".format(pin, level))

i2c_dev = I2C(I2C.I2C1, I2C.STANDARD_MODE)
expander = AW9523(i2c_dev, int_callback=int_handler)


# Set pins 4 to 7 as inputs and enable interrupts 
for i in range(4, 8):
    expander.pin(i, mode=1, interrupt_enable=1)

# Continuously perform other tasks 
while True:
    # Main Program Logic 
    utime.sleep(10)

LED Control Application

i2c_dev = I2C(I2C.I2C1, I2C.STANDARD_MODE)
expander = AW9523(i2c_dev)

# Set pins 12 to 15 to output mode to control the 
LED led_pins = [12, 13, 14, 15]
for pin in led_pins:
    expander.pin(pin, mode=0, value=0)

# LED Waterfall Light Effect while True:
for pin in led_pins:
    expander.pin(pin, value=1)  # Turn on the LED 
    utime.sleep_ms(200)
    expander.pin(pin, value=0)  # Turn off the LED 

Technical Description

1. Pin Mapping

Port	Pin Range	Register
PORTA	0-7	0x00
PORTB	8-15	0x01

2. Interruption Handling Mechanism

• Interrupt triggered by using the hardware INT pin
• Interrupt triggered when the level changes
• Interrupt callback function format: callback([pin, level])
  • pin: Pin number that has changed (0-15)
  • level: Changed level (0: low/1: high)

3. Configuration Options

Configuration Type	Value Range	Description
Pin Mode	0/1	0 = Output, 1 = Input
Output Level	0/1	0 = Low Level, 1 = High Level
Interrupt Enable	0/1	0 = Disable, 1 = Enable
Interrupt Trigger Mode	0/1	0 = Bi-directional Edge, 1 = Unidirectional Edge (Reserved)

4. I2C Address Explanation

Device Type	I2C Address
Button Driver	0x58
IO Expander	0x5B

Common Issues Troubleshooting

• Check if the I2C connections are correct.
• Confirm if the I2C address is correct (0x58 or 0x5B).
• Ensure that the interrupt_enable is set to 1.
• Verify if the INT pin configuration is correct.
• Make sure there are no blocking operations on the interrupt line within the loop.

This driver provides a complete control interface for the AW9523 GPIO expansion chip, and is suitable for various scenarios that require IO expansion.