- * LAYER_ENTER_DELAY: prevent from moving new layer
- * press release
- * Fn key sate ____|~~~~~~~~~~~~~~~~~~~|_______________
- *
- * enter_delay |======|
- * new layer
- * Layer sw ___________|~~~~~~~~~~~~|_______________
- */
-#define LAYER_ENTER_DELAY 10
-
-/*
- * LAYER_SEND_FN_TERM: send keycode if release key in this term
- * press release(send)
- * Fn key state ____|~~~~~~~~~~~~~|_______________
- * press | release(not send)
- * Fn key state ____|~~~~~~~~~~~~~|~~~~~~|__________
- * | |
- * send_fn_term |=============o==| x
+ * Parameters:
+ * enter_delay |=======|
+ * send_fn_term |================|
+ *
+ * Fn key processing cases:
+ * 1. release Fn after send_fn_term.
+ * Layer sw ___________|~~~~~~~~~~~|___
+ * Fn press ___|~~~~~~~~~~~~~~~~~~~|___
+ * Fn send ___________________________
+ *
+ * 2. release Fn in send_fn_term.(not layer used)
+ * Layer sw ___________|~~~~~~|________
+ * Fn press ___|~~~~~~~~~~~~~~|________
+ * Fn key send __________________|~|______
+ * other key press ___________________________
+ * other key send ___________________________
+ *
+ * 3. release Fn in send_fn_term.(layer used)
+ * Layer sw ___________|~~~~~~|________
+ * Fn press ___|~~~~~~~~~~~~~~|________
+ * Fn key send ___________________________
+ * Fn send ___________________________
+ * other key press _____________|~~|__________
+ * other key send _____________|~~|__________
+ *
+ * 4. press other key in ENTER_DELAY.
+ * Layer sw ___________________________
+ * Fn key press ___|~~~~~~~~~|_____________
+ * Fn key send ______|~~~~~~|_____________
+ * other key press ______|~~~|________________
+ * other key send _______|~~|________________
+ *
+ * 5. press Fn while press other key.
+ * Layer sw ___________________________
+ * Fn key press ___|~~~~~~~~~|_____________
+ * Fn key send ___|~~~~~~~~~|_____________
+ * other key press ~~~~~~~|___________________
+ * other key send ~~~~~~~|___________________
+ *
+ * 6. press Fn twice quickly and keep holding down.(repeat)
+ * Layer sw ___________________________
+ * Fn key press ___|~|____|~~~~~~~~~~~~~~~~
+ * Fn key send _____|~|__|~~~~~~~~~~~~~~~~