+## PS/2 Mouse Support
+
+Its possible to hook up a PS/2 mouse (for example touchpads or trackpoints) to your keyboard as a composite device.
+In order to do this you must first enable the option in your Makefile.
+
+ PS2_MOUSE_ENABLE = yes
+
+Then, decide whether to use interrupts (better if your microcontroller supports them) or busywait, and enable the relevant option.
+
+ PS2_USE_INT = yes
+ // PS2_USE_BUSYWAIT = yes
+
+If you're using a teensy and have hooked up the clock on your PS/2 device to D1 and the data to D0, you're all set.
+Otherwise, you will need to update the following defines in your `config.h`:
+
+ #define PS2_CLOCK_PORT PORTD
+ #define PS2_CLOCK_PIN PIND
+ #define PS2_CLOCK_DDR DDRD
+ #define PS2_CLOCK_BIT 1
+
+ #define PS2_DATA_PORT PORTD
+ #define PS2_DATA_PIN PIND
+ #define PS2_DATA_DDR DDRD
+ #define PS2_DATA_BIT 0
+
+And with `PS2_USE_INT` also define these macros:
+
+ #define PS2_INT_INIT() do { \
+ EICRA |= ((1<<ISC11) | \
+ (0<<ISC10)); \
+ } while (0)
+ #define PS2_INT_ON() do { \
+ EIMSK |= (1<<INT1); \
+ } while (0)
+ #define PS2_INT_OFF() do { \
+ EIMSK &= ~(1<<INT1); \
+ } while (0)
+ #define PS2_INT_VECT INT1_vect
+