xl9555_interrupt.ino

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#include <IoExpanderDrv.hpp>
 
#ifndef SENSOR_SDA
#define SENSOR_SDA  17
#endif
 
#ifndef SENSOR_SCL
#define SENSOR_SCL  18
#endif
 
#ifndef SENSOR_IRQ
#define SENSOR_IRQ  10
#endif
 
IoExpanderXL9555 expander;
 
void printBinary(uint8_t port, uint32_t num, int bits, bool new_line = false)
{
 
    Serial.print("Port");
    Serial.print(port);
    Serial.print(":");
 
    char binary[17];
    int i = bits - 1;
    binary[bits] = '\0';
    for (int j = 0; j < bits; j++) {
        binary[j] = '0';
    }
    for (; i >= 0; i--) {
        binary[i] = (num & 1) + '0';
        num >>= 1;
    }
 
    Serial.print(binary);
    if (new_line) {
        Serial.println();
    } else {
        Serial.print("\t");
    }
}
 
 
void setup()
{
    Serial.begin(115200);
 
    // Set the interrupt input to input pull-up
    pinMode(SENSOR_IRQ, INPUT_PULLUP);
 
    /*
    *
    *    If the device address is not known, the 0xFF parameter can be passed in.
    *
    *    XL9555_UNKNOWN_ADDRESS  = 0xFF
    *
    *    If the device address is known, the device address is given
    *
    *    XL9555_SLAVE_ADDRESS0  = 0x20
    *    XL9555_SLAVE_ADDRESS1  = 0x21
    *    XL9555_SLAVE_ADDRESS2  = 0x22
    *    XL9555_SLAVE_ADDRESS3  = 0x23
    *    XL9555_SLAVE_ADDRESS4  = 0x24
    *    XL9555_SLAVE_ADDRESS5  = 0x25
    *    XL9555_SLAVE_ADDRESS6  = 0x26
    *    XL9555_SLAVE_ADDRESS7  = 0x27
    */
    const uint8_t chip_address = XL9555_UNKNOWN_ADDRESS;
 
    if (!expander.begin(Wire, chip_address, SENSOR_SDA, SENSOR_SCL)) {
        while (1) {
            Serial.println("Failed to find XL9555 - check your wiring!");
            delay(1000);
        }
    }
 
    /*
    * Note:
    *   XL9555 has an internal pull-up resistor and maintains a high level when idle.
    *   XL9535 has a floating input internally and an uncertain state when idle, requiring an external pull-up/pull-down resistor
    * * */
 
    // Set all pins as input
    expander.configPins(IoExpanderXL9555::PORT_ALL, INPUT);
}
 
void loop()
{
    // When the interrupt occurs, we read the mask value of PORT
    if (digitalRead(SENSOR_IRQ) == LOW) {
 
        // Read 16-bit port 0 and port 1 input status
        uint16_t value = expander.digitalReadPort();
        // Read 16-bit gpio input status
        printBinary(3, value, 16, true);
 
        int i = 15;
        for (; i >= 0; i--) {
            if (!(value & 1)) {
                Serial.print("GPIO: ");
                Serial.print(15 - i);
                Serial.println(" is low");
            }
            value >>= 1;
        }
    }
}