带有XC8 v1.43的PIC16F1717，用于按键的变量

Question

I have a 4x3 matrix keypad connected to PORT B (RB1-RB7) of a PIC16F1717. I scan for keypad presses by setting each of the rows high in turn, and reading the column values. The key pressed can be decoded by matching the row and column. I am debouncing with a short delay:

while(1)
{
    //scan for key presses
    __delay_ms(10);
    ROW1 = 1;
    ROW2 = 0;
    ROW3 = 0;
    ROW4 = 0;
    if (COL1 == 1)
    {
        __delay_ms(100);
        if (COL1 == 1)
        {
            key = 1;
            keyCount = keyCount ++ 1;
        }
    }
    else if (COL2 == 1)
    {
        __delay_ms(100);
        if (COL2 == 1)
        {
            key = 2;
            keyCount = keyCount + 1;

        }
    }
    //and so on for the other rows and columns

The two variable key and keyCount keep track of which key has been pressed, and the number of keys pressed, respectively. When 4 keys have been pressed, I want to execute the following code:

    if (keyCount == 4)
    {
        LED = 1;
        __delay_ms(500);
        LED = 0;
        __delay_ms(500);
        LED = 1;
        __delay_ms(500);
        LED = 0;
        __delay_ms(500);
        LED = 1;
        __delay_ms(500);
        servoDemo();
        __delay_ms(500);
        LED = 0;
        keyCount = 0;

    }

This is also in the while(1) loop inside the main function. The problem I am having is that incrementing the keyCount does not work. Previously, I tried keyCount++ and it worked, but before that this wouldn't work either. I tried debugging by setting keyCount = 4 instead of incrementing it by one, and it worked.

Both variables were declared (and initialised) inside the main function, but outside the while(1) loop. Also, I defined the following:

//pin definitions
//////////////////////////
#define ROW1 PORTBbits.RB2
#define ROW2 PORTBbits.RB7
#define ROW3 PORTBbits.RB6
#define ROW4 PORTBbits.RB4

#define COL1 PORTBbits.RB3
#define COL2 PORTBbits.RB1
#define COL3 PORTBbits.RB5

#define SERVOSIG PORTDbits.RD0
#define LED PORTDbits.RD1

Answer 1

The problem is that you have no edge detection on your keys. That means that as long as you press a key the if statement is entered every loop cycle. Here is a small example which may give you the basic idea how to implement a loop detection.

int key[12];
int key_old[12];

read_keys(key); //function that reads the keys in

while(1)
{
    memcpy(key_old, key, 12*sizeof(key[0])); //copy key to key_old
    read_keys(key); //function that reads the keys in

    for(int i=0;i<12;i++)
    {
        if(key[i] && !key_old[i])
        {
            //positive edge on key i
        }
    }

    __delay_ms(50); //Debouncing
}

This code is not perfect but should give a basic idea as mentioned.