好的，这是我得到的代码，它告诉我按了哪个键。

#define CLOCK 6 //D-
#define DATA 7  //D+

const char keymap[][2] = {
  {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},                                                       //0
  {0,0}, {0,0}, {0,0}, {0,0}, {'`','~'}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},                                                   //10
  {0,0}, {'q','Q'}, {'1','!'}, {0,0}, {0,0}, {0,0}, {'z','Z'}, {'s','S'}, {'a','A'}, {'w','W'},                               //20
  {'2','@'}, {0,0}, {0,0}, {'c','C'}, {'x','X'}, {'d','D'}, {'e','E'}, {'4','$'}, {'3','#'}, {0,0},                           //30
  {0,0}, {' ',' '}, {'v','V'}, {'f','F'}, {'t','T'}, {'r','R'}, {'5','%'}, {0,0}, {0,0}, {'n','N'},                           //40
  {'b','B'}, {'h','H'}, {'g','G'}, {'y','Y'}, {'6','^'}, {0,0}, {0,0}, {0,0}, {'m','M'}, {'j','J'},                           //50
  {'u','U'}, {'7','&'}, {'8','*'}, {0,0}, {0,0}, {',','<'}, {'k','K'}, {'i','I'}, {'o','O'}, {'0',')'},                       //60
  {'9','('}, {0,0}, {0,0}, {'.','>'}, {'/','?'}, {'l','L'}, {';',':'}, {'p','P'}, {'-','_'}, {0,0},                           //70
  {0,0}, {0,0}, {'\'','\"'}, {0,0}, {'[','{'}, {'=','+'}, {0,0}, {0,0}, {0,0}, {0,0},                                         //80
  {0,0}, {']','}'}, {0,0}, {'\\','|'}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},                                              //90
  {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {'1','!'}, {0,0}, {'4','$'}, {'7','&'}, {0,0},                                          //100
  {0,0}, {0,0}, {'0',')'}, {'.','>'}, {'2','@'}, {'5','%'}, {'6','^'}, {'8','*'}, {0,0}, {0,0},                               //110
  {0,0}, {'+','+'}, {'3','#'}, {'-','_'},{'*','*'}, {'9','('}, {0,0}, {0,0}, {0,0}, {0,0},                                    //120
  {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},                                                       //130
};
void setup() {
  Serial.begin(9600);
  pinMode(CLOCK, INPUT_PULLUP); 
  pinMode(DATA, INPUT_PULLUP);
}
uint8_t lastscan; // doesn't work

unsigned short detectKey(){
 unsigned short scanval = 0;
 for(int i = 0; i<11; i++)
  {
    while(digitalRead(CLOCK));
    scanval |= digitalRead(DATA) << i;
    while(!digitalRead(CLOCK));
  }
  scanval >>= 1;
  scanval &= 0xFF;
  return scanval;
}

void loop() {
  bool shiftPressed= true //when the new code I need detects the shift held down;
  if(lastscan != 0xF0 && detectKey() != 0xF0)
  keymap[detectKey()][shiftPressed];
  lastscan = detectKey(); //this doesn't work to save the scancode to a variable
   /* switch(detectKey())
  {
    case 0x5A: //Enter
     Serial.println("Enter");
    break;
    case 0x66: //Backspace
      
    break;
    case 0x12:  //left shift
    while(detectKey() != 0xF0){
      shiftPressed = true;
    }
    shiftPressed = false;
  }
  */
}

下面是我使用键盘时的Arduino串行监视器：

16:47:56.832 -> 1C //hit "a"
16:47:56.924 -> F0 //let go
16:47:56.924 -> 1C 
16:47:57.948 -> 1B //hit "s"
16:47:58.119 -> F0 //let go
16:47:58.119 -> 1B
16:48:02.119 -> 23 //held down "d"
16:48:02.722 -> 23
16:48:02.758 -> 23
16:48:02.758 -> F0 //let go
16:48:02.758 -> 23

如你所见，我想使用F0来告诉系统shift被按住。shift的扫描码是12，所以shift看起来像：

12
F0
12

所以我想从一个单独的键盘Map数组中选择大写字母，同时按下另一个键，然后我想将大写字母打印为串行。