使用其指针屏蔽寄存器 - AVR 端口

Question

我正在使用一些 LED 和按钮使用微处理器 (atmega32) 编写 Simon Says 游戏。我正在尝试将指向 PORT 寄存器的指针存储在一个数组中，该函数将根据按下的按钮使用该函数来屏蔽寄存器（打开引脚以点亮 LED）。

类似于

*arrayOfPointers[1] |= 1 << mask;

但我认为这行不通，我认为这是因为我不完全理解屏蔽或指针的工作原理。

当我将指向该寄存器的指针存储在指针数组中时，如何屏蔽该寄存器？请注意我是beginner/novice，所以请像我很笨一样解释。

这里是相关代码的简化示例：

volatile uint8_t *portActivate[numberOfButtons]; //stores pointers to the PORT register
unsigned char pinActivate[numberOfButtons];  //stores the pin I want to turn on

//activateOnPress populates 2 arrays that stores the PORT and PIN corresponding to each button. (index 0 is for button 0, index 1 is for button 1, etc.)
//this will be used to tell the program which PORT and PIN to activate (output a voltage) when that button is pressed.
void activateOnPress(unsigned int buttonNumber, volatile uint8_t *activatePort, unsigned char activatePin){
    *portActivate[buttonNumber] = *activatePort;    //store the pointer to PORT register in an array
    pinActivate[buttonNumber] = activatePin;    //store the pin to be turned on at that port
}

//buttonListen will see if the specified button has been pressed (voltage on pin is 0)
//if it has, it will output a voltage to the associated pin given by my 2 arrays by masking the register pointed to by the *portActivate array.
void buttonListen(unsigned int buttonNumber,unsigned char buttonPort, unsigned char buttonPin){
    if(bit_is_clear(buttonPort, buttonPin)){    //bit_is_clear means the pin is showing 0V  
        *portActivate[buttonNumber] |= 1 << pinActivate[buttonIndex];  //this is the part thats not working!!!!
    }
}

int main(void){
    activateOnPress(1, &PORTB, PIN0);  //associate button 1 to PORT B, PIN 0, which I want to activate (output 5V) when this button is pressed

    while(1){
        buttonListen(1, PORTA, PIN1); //listen to PORT A, PIN 1. If it's pressed, then output a voltage to the port and pin associated with button 1.
    }
    return 0;
}

如有任何帮助，我将不胜感激。

Answer 1

这些年来我编写了很多设备驱动程序。所以，我想我看到了[至少一个]你的问题。

我不得不进行一些样式清理以消除长边栏评论。大多数风格指南建议宽度不要超过 80。这会使代码难以阅读。我必须这样做才能理解你的逻辑。

此外，您有两个并行数组，按按钮编号索引。我把它们合并成一个结构，这样可以更好地关联数据。

无论如何，这是经过清理的代码，其中包含错误修复（提示：#if）：

struct portpin {
    // stores pointers to the PORT register
    volatile uint8_t *portActivate;

    // stores the pin I want to turn on
    unsigned char pinActivate;
};
typedef struct portpin portpin_t;

portpin_t portlist[numberOfButtons];

// activateOnPress populates 2 arrays that stores the PORT and PIN corresponding
// to each button. (index 0 is for button 0, index 1 is for button 1, etc.)
// this will be used to tell the program which PORT and PIN to activate (output
// a voltage) when that button is pressed.
void
activateOnPress(unsigned int butno,volatile uint8_t *activatePort,
    unsigned char activatePin)
{
    portpin_t *port;

    port = &portlist[butno];

    // store the pointer to PORT register in an array
#if 0
    *port->portActivate = *activatePort;  // your code
#else
    port->portActivate = activatePort;  // fixed code
#endif

    // store the pin to be turned on at that port
    port->pinActivate = activatePin;
}

// buttonListen will see if the specified button has been pressed (voltage on
// pin is 0) if it has, it will output a voltage to the associated pin given by
// my 2 arrays by masking the register pointed to by the *portActivate array.
void
buttonListen(unsigned int butno,unsigned char buttonPort,
    unsigned char buttonPin)
{
    portpin_t *port;

    port = &portlist[butno];

    // bit_is_clear means the pin is showing 0V  
    if (bit_is_clear(buttonPort, buttonPin)) {
        // this is the part thats not working!!!!
        *port->portActivate |= 1 << port->pinActivate;
    }
}

int
main(void)
{

    // associate button 1 to PORT B, PIN 0, which I want to activate (output 5V)
    // when this button is pressed
    activateOnPress(1, &PORTB, PIN0);

    // listen to PORT A, PIN 1. If it's pressed, then output a voltage to the
    // port and pin associated with button 1.
    while (1)
        buttonListen(1, PORTA, PIN1);

    return 0;
}

使用其指针屏蔽寄存器 - AVR 端口

Masking a Register Using Its Pointer - AVR Ports

c++

pointers

avr

atmega

bitmask