PS2 keyboard reader

How do you expect to be able to capture F0?

That means that your loop must be able to exit with the most significant bit set.

But after you do "dato = dato | 0x80" you have an obligatory shift right. So it's impossible for you to ever exit that loop with the most significant bit set.

Another thing, just to make sure: are you planning to read 7 or 8 bits of data in the loop?

Because I am using a Keyboard and when I release a button I get an F0.
Thank you for your help, and yes they are 8 but with 7 I was able to see something right. Now everything works. The only problem I have is that if I don't add sendChar(' '); after sendHex(getKey()); I still get some errors. But with it everything is fine.
Thank you again.

// Read a code from a PS2 Keyboard
unsigned char getKey()
                        {
                        unsigned char n,dato;
                        n = 0;                                                                          // Inizializza il contatore
                        dato = 0;                                                               // Inizializza il dato
                        while(CLOCK);                                           // Se il clock rimane a 1 aspetta
                        while(!CLOCK);                                          // La prossima discesa e' quella con il primo bit
                                for (n =0; n < 8; n++)
                                        {
                                        while(CLOCK);                                                     // Aspetta il bit n-esimo
                                        if (DATA) dato = dato | 0x80;                   // Bitwise OR
                                        if (n < 7) dato = dato >> 1;                   // Shift a destra tranne ultimo bit
                                        while(!CLOCK);                                                                          // Aspetta la risalita del clock
                                        }
                        while(CLOCK);                                                   // Aspetta il parity bit
                        parity = DATA;
                        while(!CLOCK);
                        while(CLOCK);                                                   // Aspetta lo stop bit
                        while(!CLOCK);
                        return dato;
                        }


void main()
                        {
                        initSio();                      // Inizializza la seriale a 9600
                        while(1)
                                {

                                sendHex(getKey());
                                sendChar(' ');
                                // parity ? sendChar('t') : sendChar('f');
                                }
                        while(1);
                }

Have you never considered that you do the shift in the wrong order?

Consider what happens if you instead write:

for (n = 0; n < 8; n++) {
    while(CLOCK);            // Aspetta il bit n-esimo
    dato >>= 1;              // Make room for a new bit.
    if (DATA) dato |= 0x80;  // Assign bit if set.
    while(!CLOCK);           // Aspetta la risalita del clock
}

By the way - if your source code indents with spaces, then you are more likely to get good results when you try to paste the source code into other editors or into web pages. There are no world-wide standard for how much to indent when a tab character is seen.

You are two times right, then again this is the difference between an amateur and a professional. I am learning a lot just reading other posting too. I sow an array used as look up table to get the ascii code from the keyboard code. Thank you very much Westermark, there is neither need for a delay everithing works fine and reliably.

Now I am trying to send data to the keyboard. I just began

I know it could be too much but I would like an help for the second part.
This code sending the the commands 0xED and 0x07 to the keyboard to switch on the LEDs sometimes switches on only two LEDs but I expected to switch on the all three LEDs. Could you please tell me where could be the problem ?

void delay()
        {
         unsigned char a;
         for (a = 0; a < 200; a++);
        }
// Send a command to a PS2 keyboard
void sendCmd(unsigned char com)
                        {
                        bit parity = 1;
                        unsigned int n;
                        DATA = 1;
                        CLOCK = 1;
                        delay();
                        CLOCK = 0;
                        delay();
                        DATA = 0;

                        CLOCK = 1;       // Partenza dati

                        while(CLOCK);    // Aspetto la prima discesa
                        while(!CLOCK);   // Alla prossima discesa la tastiera si aspetta D0

                        for (n = 0; n < 8; n++)
                                {
                                DATA = com & 0x01;
                                parity = parity ^ (com & 0x01);
                                com = com >> 1;
                                while(CLOCK);
                                while(!CLOCK);
                                }
                        DATA = parity;
                        while(CLOCK);                   // Aspetto la prima discesa
                        while(!CLOCK)
                        DATA = 0;                       // Stop bit
                        while(CLOCK);                   // Aspetto la prima discesa
                        while(!CLOCK);
                        DATA = 1;
                        CLOCK = 1;
                        }