用pigpio和MCP23017进行中断读取

Question

我试着用pigpio读取来自MCP23017板的中断更改，但是我没有收到任何通知.我似乎不知道的是我需要做的初始化过程(查看文档http://ww1.microchip.com/downloads/en/devicedoc/20001952c.pdf，似乎没有使用正确的值.)。

我使用B侧作为输入，A用于输出：

i2cWriteByteData(i2cHandle, IODIRB, 0xFF); // inputs
i2cWriteByteData(i2cHandle, IODIRA, 0x00); // outputs

然后，我尝试设置中断状态(它似乎是错误的)，但我是从http://abyz.me.uk/rpi/pigpio/examples.html的'I2C Sonar‘示例中复制的。

i2cWriteByteData(i2cHandle, GPINTENB, 0x00); // Disable.
i2cWriteByteData(i2cHandle, DEFVALB, 0x00) ; // N/A.
i2cWriteByteData(i2cHandle, INTCONB, 0x00) ; // On change.

然后注册处理程序以读取更改：

gpioSetMode(ALERTPIN, PI_INPUT); /* start capacitor recharge */
gpioSetISRFuncEx(ALERTPIN, EITHER_EDGE, 0, alert, nullptr); /* call alert when state changes */

所以，我的问题是，当状态发生变化时，我的警报函数永远不会被调用(奇怪的是，当我在控制台(sudo i2cdump -y 1 0x20)上转储时，它被调用了)。

另一个问题是，我的定义是否正确？为什么两组值(Address IOCON.BANK =1和0)？MCP23017的地址是什么？(我使用的是地址IOCON.BANK = 0)：

#define IODIRA    0x00
#define IODIRB    0x01
#define IPOLA     0x02
#define IPOLB     0x03
#define GPINTENA  0x04
#define GPINTENB  0x05
#define DEFVALA   0x06
#define DEFVALB   0x07
#define INTCONA   0x08
#define INTCONB   0x09
#define IOCONA    0x0A
#define IOCONB    0x0B
#define GPPUA     0x0C
#define GPPUB     0x0D
#define INTFA     0x0E
#define INTFB     0x0F
#define INTCAPA   0x10
#define INTCAPB   0x11
#define GPIOA     0x12
#define GPIOB     0x13
#define OLATA     0x14
#define OLATB     0x15

#define ALERTPIN 26

更新

接下来，我展示了我所执行的所有代码，在阅读了文档之后，我认为我做的一切都是正确的，但是我似乎遗漏了一些初始化。奇怪的是，当按下连接到GPA0的输入按钮时，GPIOA读取的值为255 (0 0xff)，如果不按，则为0.奇怪，按压的时候应该是1，对吧？

void estimulateMCP23017(unsigned i2cAddr=0x20,unsigned i2cBus=1){
    //open i2c MCP23017
    int i2cHandle = i2cOpen(i2cBus, i2cAddr, 0);
    //open is with success if is >=0
    if(i2cHandle>=0){
        //IODIR: I/O DIRECTION REGISTER (ADDR 0x00)
        //1 = Pin is configured as an input.
        //0 = Pin is configured as an output
        //we can set each separately if we want
        //set side A as output (0)
        i2cWriteByteData(i2cHandle, IODIRA, 0xFF); // A is inputs
        //set side B as input (1)
        i2cWriteByteData(i2cHandle, IODIRB, 0x00); // B is outputs

        //turn all outputs to on (pins 0 to 7 is the bit high in 0x00-0xFF)
        i2cWriteByteData(i2cHandle, OLATA, 0x00);
        i2cWriteByteData(i2cHandle, OLATB, 0xFF);

        //now listen for changes on side (B)
        // General purpose I/O interrupt-on-change bits <7:0>
        //1 = Enables GPIO input pin for interrupt-on-change event.
        //0 = Disables GPIO input pin for interrupt-on-change event.
        i2cWriteByteData(i2cHandle, GPINTENA, 0xFF); // Enable all
        i2cWriteByteData(i2cHandle, GPINTENB, 0x00); // disable
        //Sets the compare value for pins configured for interrupt-on-change from defaults <7:0>
        //If the associated pin level is the opposite from the register bit, an interrupt occurs
        i2cWriteByteData(i2cHandle, DEFVALA, 0x00); // does not matter
        i2cWriteByteData(i2cHandle, DEFVALB, 0x00); // does not matter
        // Controls how the associated pin value is compared for interrupt-on-change <7:0>
        //1 = Pin value is compared against the associated bit in the DEFVAL register.
        //0 = Pin value is compared against the previous pin value.
        i2cWriteByteData(i2cHandle, INTCONA, 0x00) ; // On change.
        i2cWriteByteData(i2cHandle, INTCONB, 0x00) ; // does not matter.

        cout << "waiting for changes...(input value: "<<i2cReadByteData(i2cHandle, GPIOA)<<")\n";

        gpioSetMode(ALERTPIN, PI_INPUT); /* set alert pin as input */
        gpioSetISRFuncEx(ALERTPIN, EITHER_EDGE, 0, alert, nullptr); /* call alert when state changes */

        cin.get();
        i2cClose(i2cHandle);
    }
}

Answer 1

由于A银行是您的输入，您应该使用：

i2cWriteByteData(i2cHandle, GPINTENA, 0xFF); // Enable.
i2cWriteByteData(i2cHandle, INTCONA, 0x00) ; // On change.

你的定义是对的。MCP23017有两种不同的寻址寄存器的模式。使用IOCON.BANK标志设置模式。只是不要碰那一点，没有理由这么做。