CC254x GAPBOND_IO_CAP_DEFINES ------ GAP Bond Manager I/O Capabilities的含义
http://www.deyisupport.com/question_answer/wireless_connectivity/bluetooth/f/103/t/62156.aspx
#define GAPBOND_IO_CAP_DISPLAY_ONLY 0x00 //!< Display Only Device
#define GAPBOND_IO_CAP_DISPLAY_YES_NO 0x01 //!< Display and Yes and No Capable
#define GAPBOND_IO_CAP_KEYBOARD_ONLY 0x02 //!< Keyboard Only
#define GAPBOND_IO_CAP_NO_INPUT_NO_OUTPUT 0x03 //!< No Display or Input Device
#define GAPBOND_IO_CAP_KEYBOARD_DISPLAY 0x04 //!< Both Keyboard and Display Capable
#define GAPBOND_IO_CAP_DISPLAY_ONLY 0x00 //!< Display Only Device
本机仅是显示设备，本机显示密码，对端输入密码
#define GAPBOND_IO_CAP_DISPLAY_YES_NO 0x01 //!< Display and Yes and No Capable
本机显示密码，对端输入密码后，还需要本机确认是否配对
#define GAPBOND_IO_CAP_KEYBOARD_ONLY 0x02 //!< Keyboard Only
对端显示密码，本机输入密码
#define GAPBOND_IO_CAP_NO_INPUT_NO_OUTPUT 0x03 //!< No Display or Input Device
本机即不能显示密码也不能输入密码，对端只需要确定是否配对
#define GAPBOND_IO_CAP_KEYBOARD_DISPLAY 0x04 //!< Both Keyboard and Display Capable
是否是双方都要输入对方显示的密码？
