CC2541串口初始化里有个参数idleTimeout不是很明白是做什么用，具体有没有资料说明？
typedef struct
{
bool configured;
uint8 baudRate;
bool flowControl;
uint16 flowControlThreshold;
uint8 idleTimeout;
halUARTBufControl_t rx;
halUARTBufControl_t tx;
bool intEnable;
uint32 rxChRvdTime;
halUARTCBack_t callBackFunc;
}halUARTCfg_t;