Modified Arduino USB Host Shield Keyboard Example

gistfile1.cpp

// Modified from https://github.com/felis/USB_Host_Shield_2.0/blob/master/examples/HID/USBHIDBootKbd/USBHIDBootKbd.ino
// Modified to print the ASCII hex codes of the keys pressed, and to handle some of the non-printable keys.

#include <hidboot.h>
#include <usbhub.h>
// Satisfy IDE, which only needs to see the include statment in the ino.
#ifdef dobogusinclude
#include <spi4teensy3.h>
#endif

#define UHS_HID_BOOT_KEY_ESC        0x29
#define UHS_HID_BOOT_KEY_DEL        0x4C
#define UHS_HID_BOOT_KEY_BACKSPACE  0x2A
#define UHS_HID_BOOT_KEY_HOME       0x4A
#define UHS_HID_BOOT_KEY_PAGE_UP    0x4B
#define UHS_HID_BOOT_KEY_END        0x4D
#define UHS_HID_BOOT_KEY_PAGE_DN    0x4E
#define UHS_HID_BOOT_KEY_TAB        0x2B
#define UHS_HID_BOOT_KEY_CAPS       0x39


class KbdRptParser : public KeyboardReportParser
{
        void PrintKey(uint8_t mod, uint8_t key);
        uint8_t mapExtraAsciiKeys(uint8_t);

protected:
        virtual void OnControlKeysChanged(uint8_t before, uint8_t after);

	virtual void OnKeyDown	(uint8_t mod, uint8_t key);
	virtual void OnKeyUp	(uint8_t mod, uint8_t key);
	virtual void OnKeyPressed(uint8_t key);
};

void KbdRptParser::PrintKey(uint8_t m, uint8_t key)
{
    MODIFIERKEYS mod;
    *((uint8_t*)&mod) = m;
    Serial.print((mod.bmLeftCtrl   == 1) ? "C" : " ");
    Serial.print((mod.bmLeftShift  == 1) ? "S" : " ");
    Serial.print((mod.bmLeftAlt    == 1) ? "A" : " ");
    Serial.print((mod.bmLeftGUI    == 1) ? "G" : " ");

    Serial.print(" >");
    PrintHex<uint8_t>(key, 0x80);
    Serial.print("< ");

    Serial.print((mod.bmRightCtrl   == 1) ? "C" : " ");
    Serial.print((mod.bmRightShift  == 1) ? "S" : " ");
    Serial.print((mod.bmRightAlt    == 1) ? "A" : " ");
    Serial.println((mod.bmRightGUI    == 1) ? "G" : " ");
};

// Map some of the keys currently not handled by OemToAscii
uint8_t KbdRptParser::mapExtraAsciiKeys(uint8_t key) {

  switch(key) {
      case UHS_HID_BOOT_KEY_SPACE: return ' ';
      case UHS_HID_BOOT_KEY_ZERO2: return '0';
      case UHS_HID_BOOT_KEY_PERIOD: return '.';
      case UHS_HID_BOOT_KEY_ESC: return 0x1B;
      case UHS_HID_BOOT_KEY_DEL: return 0x7F;
      case UHS_HID_BOOT_KEY_BACKSPACE: return 0x08;
      case UHS_HID_BOOT_KEY_TAB: return 0x09;
  }

  return ( 0);
}


void KbdRptParser::OnKeyDown(uint8_t mod, uint8_t key)
{
    Serial.print("DN ");
    PrintKey(mod, key);
    uint8_t c = OemToAscii(mod, key);
    
    if (!c) {
      c = mapExtraAsciiKeys(key);
    }

    if (c) {
        OnKeyPressed(c);
    }

}

void KbdRptParser::OnControlKeysChanged(uint8_t before, uint8_t after) {

    MODIFIERKEYS beforeMod;
    *((uint8_t*)&beforeMod) = before;

    MODIFIERKEYS afterMod;
    *((uint8_t*)&afterMod) = after;

    if (beforeMod.bmLeftCtrl != afterMod.bmLeftCtrl) {
        Serial.println("LeftCtrl changed");
    }
    if (beforeMod.bmLeftShift != afterMod.bmLeftShift) {
        Serial.println("LeftShift changed");
    }
    if (beforeMod.bmLeftAlt != afterMod.bmLeftAlt) {
        Serial.println("LeftAlt changed");
    }
    if (beforeMod.bmLeftGUI != afterMod.bmLeftGUI) {
        Serial.println("LeftGUI changed");
    }

    if (beforeMod.bmRightCtrl != afterMod.bmRightCtrl) {
        Serial.println("RightCtrl changed");
    }
    if (beforeMod.bmRightShift != afterMod.bmRightShift) {
        Serial.println("RightShift changed");
    }
    if (beforeMod.bmRightAlt != afterMod.bmRightAlt) {
        Serial.println("RightAlt changed");
    }
    if (beforeMod.bmRightGUI != afterMod.bmRightGUI) {
        Serial.println("RightGUI changed");
    }

}

void KbdRptParser::OnKeyUp(uint8_t mod, uint8_t key)
{
    Serial.print("UP ");
    PrintKey(mod, key);
}

void KbdRptParser::OnKeyPressed(uint8_t key)
{
    Serial.print("ASCII: ");
    Serial.println(key, HEX);
};

USB     Usb;
//USBHub     Hub(&Usb);
HIDBoot<HID_PROTOCOL_KEYBOARD>    HidKeyboard(&Usb);

uint32_t next_time;

KbdRptParser Prs;

void setup()
{
    Serial.begin( 115200 );
    while (!Serial); // Wait for serial port to connect - used on Leonardo, Teensy and other boards with built-in USB CDC serial connection
    Serial.println("Start");

    if (Usb.Init() == -1)
        Serial.println("OSC did not start.");

    delay( 200 );

    next_time = millis() + 5000;

    HidKeyboard.SetReportParser(0, (HIDReportParser*)&Prs);
}

void loop()
{
    Usb.Task();
}