Make the left half send only as many bytes of key state information as required.

left/src/slave_protocol_handler.h

@@ -13,6 +13,9 @@
     #define PROTOCOL_RESPONSE_SUCCESS       0
     #define PROTOCOL_RESPONSE_GENERIC_ERROR 1
 
+    #define LEFT_KEYBOARD_HALF_KEY_COUNT (KEYBOARD_MATRIX_COLS_NUM*KEYBOARD_MATRIX_ROWS_NUM)
+    #define KEY_STATE_BUFFER_SIZE (LEFT_KEYBOARD_HALF_KEY_COUNT/8 + 1)
+
 // Variables:
 
     uint8_t SlaveRxBuffer[SLAVE_RX_BUFFER_SIZE];