instance_init 函数追下去，绝大多数的代码都在初始化如下结构体 

typedef struct{    INST_MODE mode; instance_init -ANCHOR                      //instance mode (tag or anchor)    INST_STATES testAppState ;             int instance_init_s(int mode) TA_INIT    //state machine - current state    INST_STATES nextState ;                         //state machine - next state    INST_STATES previousState ;                     //state machine - previous state    int done ;                                      //done with the current event/wait for next event to arrive       //configuration structures    dwt_config_t    configData ;        //DW1000 channel configuration    dwt_txconfig_t  configTX ;              //DW1000 TX power configuration    uint16         txantennaDelay ; //DW1000 TX antenna delay    uint16         rxantennaDelay ; //DW1000 RX antenna delay    uint8 antennaDelayChanged;    // "MAC" features    uint8 frameFilteringEnabled ; //frame filtering is enabled   // Is sleeping between frames enabled?    uint8 sleep_en; instance_init 1   //timeouts and delays   int tagSleepTime_ms;   instancesettagsleepdelay  500//in milliseconds   int tagBlinkSleepTime_ms; instancesettagsleepdelay  1000   //this is the delay used for the delayed transmit (when sending the ranging init, response, and final messages)   uint64 rnginitReplyDelay ;   uint64 finalReplyDelay ;   uint64 responseReplyDelay ;   int finalReplyDelay_ms ;   // xx_sy the units are 1.0256 us    uint32 txToRxDelayAnc_sy ;    // this is the delay used after sending a response and turning on the receiver to receive final    uint32 txToRxDelayTag_sy ;    // this is the delay used after sending a poll and turning on the receiver to receive response    int rnginitW4Rdelay_sy ; // this is the delay used after sending a blink and turning on the receiver to receive the ranging init message    int fwtoTime_sy ;     //this is final message duration (longest out of ranging messages)    int fwtoTimeB_sy ;  //this is the ranging init message duration    uint32 delayedReplyTime;                 // delayed reply time of delayed TX message - high 32 bits    uint32 rxTimeouts ; instanceclearcounts 0    // - not used in the ARM code uint32 responseTimeouts ;    // Pre-computed frame lengths for frames involved in the ranging process,    // in microseconds.    uint32 fl_us[FRAME_TYPE_NB];    //message structures used for transmitted messages#if (USING_64BIT_ADDR == 1)      srd_msg_dlsl rng_initmsg ;     // ranging init message (destination long, source long)      srd_msg_dlsl msg ;                    // simple 802.15.4 frame structure (used for tx message) - using long addresses#else      srd_msg_dlss rng_initmsg ;  // ranging init message (destination long, source short)      srd_msg_dsss msg ;                           // simple 802.15.4 frame structure (used for tx message) - using short addresses#endif    iso_IEEE_EUI64_blink_msg blinkmsg ; // frame structure (used for tx blink message)    //messages used in "fast" ranging ...     srd_msg_dlss rnmsg ; // ranging init message structure     srd_msg_dsss msg_f ; // ranging message with 16-bit addresses - used for "fast" ranging      //Tag function address/message configuration     uint8   eui64[8];                                // devices EUI 64-bit address     uint16  tagShortAdd ;                 // Tag's short address (16-bit) used when USING_64BIT_ADDR == 0     uint16  psduLength ;                        // used for storing the frame length     uint8   frame_sn; instanceclearcounts         0      // modulo 256 frame sequence number - it is incremented for each new frame transmittion     uint16  panid ;        instance_init 0          xdeca                          // panid used in the frames     uint8 relpyAddress[8] ;         // address of the anchor the tag is ranging with    //64 bit timestamps    //union of TX timestamps     union {              uint64 txTimeStamp ;                   // last tx timestamp              uint64 tagPollTxTime ;                 // tag's poll tx timestamp              uint64 anchorRespTxTime ;        // anchor's reponse tx timestamp         }txu;     uint64 anchorRespRxTime ;        // receive time of response message     uint64 tagPollRxTime ;          // receive time of poll message      //32 bit timestamps (when "fast" ranging is used)     uint32 tagPollTxTime32l ;      // poll tx time - low 32 bits     uint32 tagPollRxTime32l ;      // poll rx time - low 32 bits     uint32 anchorRespTxTime32l ;    // response tx time - low 32 bits     uint32 anchResp1RxTime32l ;                   // response 1 rx time - low 32 bits     //application control parameters     uint8         wait4ack ;         instance_init 0         // if this is set to DWT_RESPONSE_EXPECTED, then the receiver will turn on automatically after TX completion     uint8         instToSleep;      instance_init 0             // if set the instance will go to sleep before sending the blink/poll message     uint8         stoptimer;        instance_init 0                                      // stop/disable an active timer     uint8         instancetimer_en;   instance_init 0          // enable/start a timer     uint32       instancetimer;                            // e.g. this timer is used to timeout Tag when in deep sleep so it can send the next poll message     uint32       instancetimer_saved;    // - not used in the ARM code    //uint8      deviceissleeping;               // this disabled reading/writing to DW1000 while it is in sleep mode     // (DW1000 will wake on chip select so need to disable and chip select line activity)     uint8         gotTO;                                           // got timeout event     uint8   responseRxNum;                          // response number    //diagnostic counters/data, results and logging    int32 tof32 ;    int64 tof ; instance_init 0    double clockOffset ; instance_init 0    uint32 blinkRXcount ; instcleartaglist 0    int txmsgcount; instanceclearcounts 0    int    rxmsgcount; instanceclearcounts 0    int lateTX; instanceclearcounts 0    int lateRX; instanceclearcounts 0    double adist[RTD_MED_SZ] ;    double adist4[4] ;    double longTermRangeSum ; instanceclearcounts 0    int longTermRangeCount ; instanceclearcounts 0    int tofindex ; instance_init 0   instanceclearcounts 0    int tofcount ; instance_init 0   instanceclearcounts 0    int last_update ;           // detect changes to status report    double idistmax; instanceclearcounts 0    double idistmin; instanceclearcounts 1000    double idistance ; // instantaneous distance    int newrange;    int norange;    int newrangeancaddress; //last 4 bytes of anchor address    int newrangetagaddress; //last 4 bytes of tag address     // - not used in the ARM code uint32       lastReportTime;    int respPSC;    //if set to 1 then it means that DW1000 is in DEEP_SLEEP    //so the ranging has finished and micro can output on USB/LCD    //if sending data to LCD during ranging this limits the speed of ranging    uint8 canprintinfo ;    //devicelogdata_t devicelogdata;    uint8 tagToRangeWith;   instcleartaglist 0//it is the index of the tagList array which contains the address of the Tag we are ranging with    uint8 tagListLen ; instcleartaglist 0    uint8 anchorListIndex ; int instance_init_s(int mode) 0    uint8 tagList[TAG_LIST_SIZE][8]; instcleartaglist 0    //event queue - used to store DW1000 events as they are processed by the dw_isr/callback functions    event_data_t dwevent[MAX_EVENT_NUMBER]; instance_clearevents 0 //this holds any TX/RX events and associated message data    event_data_t saved_dwevent; //holds an RX event while the ACK is being sent    uint8 dweventIdxOut; instance_clearevents 0    uint8 dweventIdxIn; instance_clearevents 0    uint8 dweventPeek; instance_clearevents 0    uint8 monitor; instance_init 0    uint32 timeofTx ;    int dwIDLE;} instance_data_t ;

上述默认初始化设别为，但是后面接着会根据拨码开关再次决定设备类型

if(s1switch & SWS1_ANC_MODE){     instance_mode = ANCHOR;     led_on(LED_PC6);}else{    instance_mode = TAG;    led_on(LED_PC7);  }

并再次调用函数设置设备类型

//Set this instance role as the Tag, Anchor or Listenervoid instancesetrole(int inst_mode){    // assume instance 0, for this    instance_data[0].mode =  inst_mode;   // set the role}

注意:设置全部都保存在结果体instance_data中，如果我们想扩充设备，那就需要修改这个家伙的数组了。 

后面是初始化init 结构体

int instance_init_s(int mode){    int instance = 0 ;    instance_data[instance].mode =  mode;     //上面已经设定过了     // assume anchor,    instance_data[instance].testAppState = TA_INIT ; //后面状态机会用到这个。     // if using auto CRC check (DWT_INT_RFCG and DWT_INT_RFCE) are used instead of DWT_INT_RDFR flag    // other errors which need to be checked (as they disable receiver) are    //dwt_setinterrupt(DWT_INT_TFRS | DWT_INT_RFCG | (DWT_INT_SFDT | DWT_INT_RFTO /*| DWT_INT_RXPTO*/), 1);    //暂时不看具体寄存器设定    dwt_setinterrupt(DWT_INT_TFRS | DWT_INT_RFCG | (DWT_INT_ARFE | DWT_INT_RFSL | DWT_INT_SFDT | DWT_INT_RPHE | DWT_INT_RFCE | DWT_INT_RFTO /*| DWT_INT_RXPTO*/), 1);     //this is platform dependent - only program if DW EVK/EVB    dwt_setleds(3) ; //configure the GPIOs which control the LEDs on EVBs    //非常重要，这个是两个回调函数       dwt_setcallbacks(instance_txcallback, instance_rxcallback);    //非常重要，这个应用层主要函数    instance_setapprun(testapprun_s);     instance_data[instance].anchorListIndex = 0 ;     //sample test calibration functions    //xtalcalibration();        //powertest();    return 0 ;}

回调函数设定

void dwt_setcallbacks(void (*txcallback)(const dwt_callback_data_t *), void (*rxcallback)(const dwt_callback_data_t *)){    dw1000local.dwt_txcallback = txcallback;    dw1000local.dwt_rxcallback = rxcallback;}

应用层函数设定

void instance_setapprun(int (*apprun_fn)(instance_data_t *inst, int message)){         int instance = 0 ;         instance_localdata[instance].testapprun_fn = apprun_fn;}

设定这些函数，只是提供入口，此时还不会执行。但是RX TX 回调函数是通过中断触发的，设定后可能会立马执行，这个我们后续看代码分析。 接着返回函数上层追踪 

instance_init_s(instance_mode); dr_mode = decarangingmode(s1switch);//NOTE: Channel 5 is not supported for the non-discovery modeint decarangingmode(uint8 s1switch){    int mode = 0;    if(s1switch & SWS1_SHF_MODE)    {        mode = 1;    }    if(s1switch & SWS1_64M_MODE)    {        mode = mode + 2;    }    if(s1switch & SWS1_CH5_MODE)    {        mode = mode + 4;    }    return mode;}

我们暂时还不确定目前sw组合，看代码不难理解，后续我们再分析这一块。

instConfig.channelNumber = chConfig[dr_mode].channel ;instConfig.preambleCode = chConfig[dr_mode].preambleCode ;instConfig.pulseRepFreq = chConfig[dr_mode].prf ;instConfig.pacSize = chConfig[dr_mode].pacSize ;instConfig.nsSFD = chConfig[dr_mode].nsSFD ;instConfig.sfdTO = chConfig[dr_mode].sfdTO ;instConfig.dataRate = chConfig[dr_mode].datarate ;instConfig.preambleLen = chConfig[dr_mode].preambleLength ;instance_config(&instConfig) ;       // Set operating channel etc

根据上面按键sw 确定某一种模式，然后将chConfig 全局变量的一部分提取出来，放到instConfig中，然后调用instance_config配置，这些都是DWM1000 工作必须配置，需要配合datasheet 查看，具体我们这里就不解释了，我们注重的逻辑

调用instance_config我们就认为RF 相关的参数已经正确配置到DWM1000了。 

instancesettagsleepdelay(POLL_SLEEP_DELAY, BLINK_SLEEP_DELAY); //set the Tag sleep time(500,1000)

其实从函数内容来看，还是在初始化结构体instace_data。

// -------------------------------------------------------------------------------------------------------------------// function to set the tag sleep time (in ms)//void instancesettagsleepdelay(int sleepdelay, int blinksleepdelay) //sleep in ms{    int instance = 0 ;    instance_data[instance].tagSleepTime_ms = sleepdelay ;    instance_data[instance].tagBlinkSleepTime_ms = blinksleepdelay ;}

Inittestapplication 最后一个函数instance_init_timings

从下面的解释可以看出还是初始化相关，这个函数稍微复杂点，我们暂时先不看。

// Pre-compute frame lengths, timeouts and delays needed in ranging process.// /!\ This function assumes that there is no user payload in the frame.void instance_init_timings(void)　　

 现在我们就基本分析完了inittestapplication， 正如它的名字一样，这个主要是init， 一些关键参数的值我们在上面的结构体中也有标注