#include "Code_LEDLock.h" /* USB_LED_bit are codes from http://www.usb.org/developers/hidpage/HID1_11.pdf keyboard output report */ Code_LEDLock::Code_LEDLock(const uint16_t scancode, LED& refLED) : scancode(scancode), refLED(refLED) { switch (scancode) //initilize USB_LED_bit for given scancode { case KEY_NUM_LOCK: USB_LED_bit = 1<<0; break; case KEY_CAPS_LOCK: USB_LED_bit = 1<<1; break; case KEY_SCROLL_LOCK: USB_LED_bit = 1<<2; break; /* guessing at these case names: case KEY_COMPOSE: //for separate accent keys USB_LED_bit = 1<<3; break; break; case KEY_KANA: //for Japanese keyboards USB_LED_bit = 1<<4; break; break; */ } } void Code_LEDLock::press() { Keyboard.press(scancode); updateLED(); } void Code_LEDLock::release() { Keyboard.release(scancode); } /* This comment is for Arduino board, because Arduino boards may need a different implementation. updateLED() has NOT been tested on an Arduino board. updateLED() has been tested on teensy 2.0 (not an Arduino board). The variable "keyboard_leds" is in /opt/arduino-1.6.7/hardware/teensy/avr/cores/usb_hid/usb.c // 1=num lock, 2=caps lock, 4=scroll lock, 8=compose, 16=kana https://forum.pjrc.com/threads/25368-How-do-I-receive-a-numlock-capslock-LED-signal-from-the-PC The word "keyboard_leds does not appear in "Arduino\hardware\arduino\cores\ This shows how to hack KeyReport in Arduino: https://www.sparkfun.com/tutorials/337 TMK firmware, which is not Arduino, uses variable "usb_led" instead of "keyboard_leds" http://deskthority.net/workshop-f7/how-to-build-your-very-own-keyboard-firmware-t7177.html >usb_led */ void Code_LEDLock::updateLED() const { /* KEY_SCROLL_LOCK is not working on Linux with Teensy2.0. This debug code prints "keyboard_leds=0" when scrollLock is pressed: Keyboard.print(F(" keyboard_leds=")); Keyboard.print(keyboard_leds); //KEY_NUM_LOCK:1, KEY_CAPS_LOCK:2, KEY_SCROLL_LOCK:0 Keyboard.print(" "); */ if (keyboard_leds & USB_LED_bit) //if USB_LED_bit is set { refLED.off(); //LED on-off seem inverted, but it works for active low and active high } else { refLED.on(); } }