/*! ---------------------------------------------------------------------------- * @file main.c * @brief Double-sided two-way ranging (DS TWR) initiator example code * * This is a simple code example which acts as the initiator in a DS TWR distance measurement exchange. This application sends a "poll" * frame (recording the TX time-stamp of the poll), and then waits for a "response" message expected from the "DS TWR responder" example * code (companion to this application). When the response is received its RX time-stamp is recorded and we send a "final" message to * complete the exchange. The final message contains all the time-stamps recorded by this application, including the calculated/predicted TX * time-stamp for the final message itself. The companion "DS TWR responder" example application works out the time-of-flight over-the-air * and, thus, the estimated distance between the two devices. * * @attention * * Copyright 2015 (c) Decawave Ltd, Dublin, Ireland. * * All rights reserved. * * @author Decawave */ #include #include #include "deca_device_api.h" #include "deca_regs.h" #include "deca_sleep.h" #include "lcd.h" #include "port.h" #include "Rcc_Nvic_Systick.h" #include "Usart.h" #include "Spi.h" #include "dw_driver.h" #include "led.h" /* Example application name and version to display on LCD screen. */ #define APP_NAME "DS TWR INIT v1.1" /* Inter-ranging delay period, in milliseconds. */ #define RNG_DELAY_MS 100 /* Default communication configuration. We use here EVK1000's default mode (mode 3). */ static dwt_config_t config = { 2, /* Channel number. */ DWT_PRF_64M, /* Pulse repetition frequency. */ DWT_PLEN_1024, /* Preamble length. */ DWT_PAC32, /* Preamble acquisition chunk size. Used in RX only. */ 9, /* TX preamble code. Used in TX only. */ 9, /* RX preamble code. Used in RX only. */ 1, /* Use non-standard SFD (Boolean) */ DWT_BR_110K, /* Data rate. */ DWT_PHRMODE_STD, /* PHY header mode. */ (1025 + 64 - 32) /* SFD timeout (preamble length + 1 + SFD length - PAC size). Used in RX only. */ }; /* Default antenna delay values for 64 MHz PRF. See NOTE 1 below. */ #define TX_ANT_DLY 0 #define RX_ANT_DLY 32899 static uint8 rx_poll_msg[] = {0x00, 0x88, 0, 0xCA, 0xDE, 'W', 'A', 'V', 'E', 0x21, 0, 0}; static uint8 tx_resp_msg[] = {0x41, 0x88, 0, 0xCA, 0xDE, 'V', 'E', 'W', 'A', 0x10, 0x02, 0, 0, 0, 0}; static uint8 rx_final_msg[] = {0x41, 0x88, 0, 0xCA, 0xDE, 'W', 'A', 'V', 'E', 0x23, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; /* Frames used in the ranging process. See NOTE 2 below. */ static uint8 tx_poll_msg[] = {0x00, 0x88, 0, 0xCA, 0xDE, 'W', 'A', 'V', 'E', 0x21, 0, 0}; static uint8 rx_resp_msg[] = {0x41, 0x88, 0, 0xCA, 0xDE, 'V', 'E', 'W', 'A', 0x10, 0x02, 0, 0, 0, 0}; static uint8 tx_final_msg[] = {0x41, 0x88, 0, 0xCA, 0xDE, 'W', 'A', 'V', 'E', 0x23, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; /* Length of the common part of the message (up to and including the function code, see NOTE 2 below). */ typedef signed long long int64; typedef unsigned long long uint64; static uint64 poll_rx_ts; static uint64 resp_tx_ts; static uint64 final_rx_ts; static double tof; static double distance, dist2; int16_t dist[8]; #define ALL_MSG_COMMON_LEN 10 /* Indexes to access some of the fields in the frames defined above. */ #define ALL_MSG_SN_IDX 2 #define FINAL_MSG_POLL_TX_TS_IDX 10 #define FINAL_MSG_RESP_RX_TS_IDX 14 #define FINAL_MSG_FINAL_TX_TS_IDX 18 #define FINAL_MSG_TS_LEN 4 /* Frame sequence number, incremented after each transmission. */ static uint32 frame_seq_nb = 0; /* Buffer to store received response message. * Its size is adjusted to longest frame that this example code is supposed to handle. */ #define RX_BUF_LEN 20 #define RX_BUF_LEN2 24 static uint8 rx_buffer[RX_BUF_LEN + 4]; /* Hold copy of status register state here for reference, so reader can examine it at a breakpoint. */ static uint32 status_reg = 0; /* UWB microsecond (uus) to device time unit (dtu, around 15.65 ps) conversion factor. * 1 uus = 512 / 499.2 µs and 1 µs = 499.2 * 128 dtu. */ #define UUS_TO_DWT_TIME 65536 /* Delay between frames, in UWB microseconds. See NOTE 4 below. */ /* This is the delay from the end of the frame transmission to the enable of the receiver, as programmed for the DW1000's wait for response feature. */ #define POLL_TX_TO_RESP_RX_DLY_UUS 150 /* This is the delay from Frame RX timestamp to TX reply timestamp used for calculating/setting the DW1000's delayed TX function. This includes the * frame length of approximately 2.66 ms with above configuration. */ #define RESP_RX_TO_FINAL_TX_DLY_UUS 4100 /* Receive response timeout. See NOTE 5 below. */ #define RESP_RX_TIMEOUT_UUS 14700 #define POLL_RX_TO_RESP_TX_DLY_UUS 3600 /* This is the delay from the end of the frame transmission to the enable of the receiver, as programmed for the DW1000's wait for response feature. */ #define RESP_TX_TO_FINAL_RX_DLY_UUS 500 /* Receive final timeout. See NOTE 5 below. */ #define FINAL_RX_TIMEOUT_UUS 4300 #define SPEED_OF_LIGHT 299702547 /* Time-stamps of frames transmission/reception, expressed in device time units. * As they are 40-bit wide, we need to define a 64-bit int type to handle them. */ typedef unsigned long long uint64; static uint64 poll_tx_ts; static uint64 resp_rx_ts; static uint64 final_tx_ts; /* Declaration of static functions. */ static uint64 get_tx_timestamp_u64(void); static uint64 get_rx_timestamp_u64(void); static void final_msg_set_ts(uint8 *ts_field, uint64 ts); /*! ------------------------------------------------------------------------------------------------------------------ * @fn main() * * @brief Application entry point. * * @param none * * @return none */ static void final_msg_get_ts(const uint8 *ts_field, uint32 *ts) { int i; *ts = 0; for (i = 0; i < FINAL_MSG_TS_LEN; i++) { *ts += ts_field[i] << (i * 8); } } //void GPIO_Toggle(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin) //{ // GPIO_WriteBit(GPIOx, GPIO_Pin, (BitAction)!GPIO_ReadOutputDataBit(GPIOx, GPIO_Pin)); //} int fputc(int ch, FILE *f) { USART_SendData(USART1, (unsigned char) ch);// USART1 ???? USART2 ? while (!(USART1->SR & USART_FLAG_TXE)); return (ch); } void USART_putc(char c) { //while(!(USART2->SR & 0x00000040)); //USART_SendData(USART2,c); /* e.g. write a character to the USART */ USART_SendData(USART1, c); /* Loop until the end of transmission */ while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET) ; } void USART_puts(uint8_t *s, uint8_t len) { int i; for(i = 0; i < len; i++) { USART_putc(s[i]); } } int ld[100]; int LP(int tmp, uint8_t channel) { int data; data = 0.7 * ld[channel] + 0.3 * tmp; ld[channel] = data; return data; } uint16_t Checksum_u16(uint8_t *pdata, uint32_t len) { uint16_t sum = 0; uint32_t i; for(i = 0; i < len; i++) sum += pdata[i]; sum = ~sum; return sum; } void LED_blink(void) { uint8_t ii; for (ii = 0; ii < 10; ii++) { GPIO_Toggle(GPIOA, LED_PIN); deca_sleep(100); } } //extern volatile unsigned long time32_reset; extern uint8_t Work_Mode; uint32 frame_len; uint8_t send[9]; char dist_str[16] = {0}; int32_t dis; double dID; uint8_t TAG_ID, ANCHOR_ID, jumptime = 0; uint32_t rec_dist, hex_dist; uint16_t check; void Device_Init(void) { Rcc_Init(); Nvic_Init(); Systick_Init(); Led_Init(); DW_GPIO_Init(); Usart_Init(); Spi_Init(); GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE); } int main(void) { Device_Init(); // RCC_ClocksTypeDef RCC_Clocks; /* Start with board specific hardware init. */ // peripherals_init();//³õʼ»¯ÍâÉè // RCC_GetClocksFreq(&RCC_Clocks); /* Display application name on LCD. */ // lcd_display_str(APP_NAME); /* Reset and initialise DW1000. * For initialisation, DW1000 clocks must be temporarily set to crystal speed. After initialisation SPI rate can be increased for optimum * performance. */ Reset_DW1000();//ÖØÆôDW1000 /* Target specific drive of RSTn line into DW1000 low for a period. */ // spi_set_rate_low();//½µµÍSPIƵÂÊ dwt_initialise(DWT_LOADUCODE);//³õʼ»¯DW1000 // spi_set_rate_high();//»Ø¸´SPIƵÂÊ Spi_ChangePrescaler(SPIx_PRESCALER_FAST); //ÉèÖÃΪ¿ìËÙģʽ /* Configure DW1000. See NOTE 6 below. */ dwt_configure(&config);//ÅäÖÃDW1000 /* Apply default antenna delay value. See NOTE 1 below. */ dwt_setrxantennadelay(RX_ANT_DLY); //ÉèÖýÓÊÕÌìÏßÑÓ³Ù dwt_settxantennadelay(TX_ANT_DLY); //ÉèÖ÷¢ÉäÌìÏßÑÓ³Ù /* Set expected response's delay and timeout. See NOTE 4 and 5 below. * As this example only handles one incoming frame with always the same delay and timeout, those values can be set here once for all. */ dwt_setrxaftertxdelay(POLL_TX_TO_RESP_RX_DLY_UUS);//ÉèÖ÷¢Ëͺó¿ªÆô½ÓÊÕ£¬²¢É趨ÑÓ³Ùʱ¼ä dwt_setrxtimeout(RESP_RX_TIMEOUT_UUS); //ÉèÖýÓÊÕ³¬Ê±Ê±¼ä send[0] = 0x6D; //´®¿ÚÊý¾Ý send[1] = 0xD6; //´®¿ÚÊý¾Ý tx_poll_msg[6] = ANCHOR_ID; //UWB POLL °üÊý¾Ý rx_resp_msg[6] = ANCHOR_ID; //UWB RESPONSE °üÊý¾Ý tx_final_msg[6] = ANCHOR_ID;//UWB Fianl °üÊý¾Ý rx_poll_msg[6] = ANCHOR_ID; tx_resp_msg[6] = ANCHOR_ID; rx_final_msg[6] = ANCHOR_ID; tx_poll_msg[5] = TAG_ID;//UWB POLL °üÊý¾Ý rx_resp_msg[5] = TAG_ID;//UWB RESPONSE °üÊý¾Ý tx_final_msg[5] = TAG_ID;//UWB Fianl °üÊý¾Ý /* Loop forever initiating ranging exchanges. */ LED_blink(); if(!Work_Mode) //Ñ¡Ôñ·¢ËÍģʽ£¨TAG±êÇ©£©»¹ÊǽÓÊÕģʽ(ANCHOR»ùÕ¾) { while (1) //·¢ËÍģʽ(TAG±êÇ©) { /* Write frame data to DW1000 and prepare transmission. See NOTE 7 below. */ tx_poll_msg[ALL_MSG_SN_IDX] = frame_seq_nb; dwt_writetxdata(sizeof(tx_poll_msg), tx_poll_msg, 0);//½«Poll°üÊý¾Ý´«¸øDW1000£¬½«ÔÚ¿ªÆô·¢ËÍʱ´«³öÈ¥ dwt_writetxfctrl(sizeof(tx_poll_msg), 0);//ÉèÖó¬¿í´ø·¢ËÍÊý¾Ý³¤¶È /* Start transmission, indicating that a response is expected so that reception is enabled automatically after the frame is sent and the delay * set by dwt_setrxaftertxdelay() has elapsed. */ dwt_starttx(DWT_START_TX_IMMEDIATE | DWT_RESPONSE_EXPECTED);//¿ªÆô·¢ËÍ£¬·¢ËÍÍê³ÉºóµÈ´ýÒ»¶Îʱ¼ä¿ªÆô½ÓÊÕ£¬µÈ´ýʱ¼äÔÚdwt_setrxaftertxdelayÖÐÉèÖà /* We assume that the transmission is achieved correctly, poll for reception of a frame or error/timeout. See NOTE 8 below. */ while (!((status_reg = dwt_read32bitreg(SYS_STATUS_ID)) & (SYS_STATUS_RXFCG | SYS_STATUS_ALL_RX_ERR)))//²»¶Ï²éѯоƬ״ֱ̬µ½³É¹¦½ÓÊÕ»òÕß·¢Éú´íÎó { }; /* Increment frame sequence number after transmission of the poll message (modulo 256). */ frame_seq_nb++; if (status_reg & SYS_STATUS_RXFCG)//Èç¹û³É¹¦½ÓÊÕ { uint32 frame_len; /* Clear good RX frame event and TX frame sent in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_RXFCG | SYS_STATUS_TXFRS);//Çå³þ¼Ä´æÆ÷±ê־λ /* A frame has been received, read it into the local buffer. */ frame_len = dwt_read32bitreg(RX_FINFO_ID) & RX_FINFO_RXFLEN_MASK; //»ñµÃ½ÓÊÕµ½µÄÊý¾Ý³¤¶È dwt_readrxdata(rx_buffer, frame_len, 0); //¶ÁÈ¡½ÓÊÕÊý¾Ý /* Check that the frame is the expected response from the companion "DS TWR responder" example. * As the sequence number field of the frame is not relevant, it is cleared to simplify the validation of the frame. */ rx_buffer[ALL_MSG_SN_IDX] = 0; if (rx_buffer[9] == 0x10) //ÅжϽÓÊÕµ½µÄÊý¾ÝÊÇ·ñÊÇresponseÊý¾Ý { uint32 final_tx_time; /* Retrieve poll transmission and response reception timestamp. */ poll_tx_ts = get_tx_timestamp_u64(); //»ñµÃPOLL·¢ËÍʱ¼äT1 resp_rx_ts = get_rx_timestamp_u64(); //»ñµÃRESPONSE½ÓÊÕʱ¼äT4 memcpy(&dist[TAG_ID], &rx_buffer[11], 2); /* Compute final message transmission time. See NOTE 9 below. */ final_tx_time = (resp_rx_ts + (RESP_RX_TO_FINAL_TX_DLY_UUS * UUS_TO_DWT_TIME)) >> 8;//¼ÆËãfinal°ü·¢ËÍʱ¼ä£¬T5=T4+Treply2 dwt_setdelayedtrxtime(final_tx_time);//ÉèÖÃfinal°ü·¢ËÍʱ¼äT5 /* Final TX timestamp is the transmission time we programmed plus the TX antenna delay. */ final_tx_ts = (((uint64)(final_tx_time & 0xFFFFFFFE)) << 8) + TX_ANT_DLY;//final°üʵ¼Ê·¢ËÍʱ¼äÊǼÆËãʱ¼ä¼ÓÉÏ·¢ËÍÌìÏßdelay /* Write all timestamps in the final message. See NOTE 10 below. */ final_msg_set_ts(&tx_final_msg[FINAL_MSG_POLL_TX_TS_IDX], poll_tx_ts);//½«T1£¬T4£¬T5дÈë·¢ËÍÊý¾Ý final_msg_set_ts(&tx_final_msg[FINAL_MSG_RESP_RX_TS_IDX], resp_rx_ts); final_msg_set_ts(&tx_final_msg[FINAL_MSG_FINAL_TX_TS_IDX], final_tx_ts); /* Write and send final message. See NOTE 7 below. */ tx_final_msg[ALL_MSG_SN_IDX] = frame_seq_nb; dwt_writetxdata(sizeof(tx_final_msg), tx_final_msg, 0);//½«·¢ËÍÊý¾ÝдÈëDW1000 dwt_writetxfctrl(sizeof(tx_final_msg), 0);//É趨·¢ËÍÊý¾Ý³¤¶È dwt_starttx(DWT_START_TX_DELAYED);//É趨ΪÑÓ³Ù·¢ËÍ if (GPIO_ReadInputDataBit(GPIOA, SW2) != RESET) //ͨ¹ý²¦Â뿪¹ØÅжÏÊý¾ÝÊä³ö¸ñʽ { dID = TAG_ID; printf("TAG_ID: %2.0f ", dID); dID = ANCHOR_ID; printf("ANCHOR_ID: %2.0f ", dID); printf("Distance: %5.0f cm\n", (double)dist[TAG_ID]); } else { send[2] = ANCHOR_ID; send[3] = TAG_ID; memcpy(&send[4], &dist[TAG_ID], 2); check = Checksum_u16(&send[2], 6); memcpy(&send[8], &check, 2); USART_puts(send, 10); } /* Poll DW1000 until TX frame sent event set. See NOTE 8 below. */ while (!(dwt_read32bitreg(SYS_STATUS_ID) & SYS_STATUS_TXFRS))//²»¶Ï²éѯоƬ״ֱ̬µ½·¢ËÍÍê³É { }; /* Clear TXFRS event. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_TXFRS);//Çå³þ±ê־λ /* Increment frame sequence number after transmission of the final message (modulo 256). */ frame_seq_nb++; // time32_reset = 0; GPIO_Toggle(GPIOA, LED_PIN); //LEDÉÁ˸ jumptime = 0; } else { jumptime = 5; //Èç¹ûͨѶʧ°Ü£¬½«¼ä¸ôʱ¼äÔö¼Ó5ms£¬±Ü¿ªÒòΪ¶à±êǩͬʱ·¢ËÍÒýÆðµÄ³åÍ»¡£ } } else { /* Clear RX error events in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_ALL_RX_ERR); jumptime = 5; } /* Execute a delay between ranging exchanges. */ deca_sleep(RNG_DELAY_MS + jumptime); //ÐÝÃ߹̶¨Ê±¼ä } } else { while (1)//½ÓÊÕģʽ(ANCHOR»ùÕ¾) { /* Clear reception timeout to start next ranging process. */ dwt_setrxtimeout(0);//É趨½ÓÊÕ³¬Ê±Ê±¼ä£¬0λûÓг¬Ê±Ê±¼ä /* Activate reception immediately. */ dwt_rxenable(0);//´ò¿ª½ÓÊÕ /* Poll for reception of a frame or error/timeout. See NOTE 7 below. */ while (!((status_reg = dwt_read32bitreg(SYS_STATUS_ID)) & (SYS_STATUS_RXFCG | SYS_STATUS_ALL_RX_ERR)))//²»¶Ï²éѯоƬ״ֱ̬µ½½ÓÊճɹ¦»òÕß³öÏÖ´íÎó { }; if (status_reg & SYS_STATUS_RXFCG)//³É¹¦½ÓÊÕ { /* Clear good RX frame event in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_RXFCG);//Çå³þ±ê־λ /* A frame has been received, read it into the local buffer. */ frame_len = dwt_read32bitreg(RX_FINFO_ID) & RX_FINFO_RXFL_MASK_1023;//»ñµÃ½ÓÊÕÊý¾Ý³¤¶È dwt_readrxdata(rx_buffer, frame_len, 0);//¶ÁÈ¡½ÓÊÕÊý¾Ý /* Check that the frame is a poll sent by "DS TWR initiator" example. * As the sequence number field of the frame is not relevant, it is cleared to simplify the validation of the frame. */ rx_buffer[ALL_MSG_SN_IDX] = 0; TAG_ID = rx_buffer[5]; rx_poll_msg[5] = TAG_ID;//Ϊ¶à±êǩͨѶ·þÎñ£¬·ÀÖ¹Ò»´ÎͨѶÖнÓÊÕµ½²»Í¬ID±êÇ©µÄÊý¾Ý tx_resp_msg[5] = TAG_ID; rx_final_msg[5] = TAG_ID; if (rx_buffer[9] == 0x21) //ÅжÏÊÇ·ñÊÇpoll°üÊý¾Ý { uint32 resp_tx_time; /* Retrieve poll reception timestamp. */ poll_rx_ts = get_rx_timestamp_u64();//»ñµÃPoll°ü½ÓÊÕʱ¼äT2 /* Set send time for response. See NOTE 8 below. */ resp_tx_time = (poll_rx_ts + (POLL_RX_TO_RESP_TX_DLY_UUS * UUS_TO_DWT_TIME)) >> 8;//¼ÆËãResponse·¢ËÍʱ¼äT3¡£ dwt_setdelayedtrxtime(resp_tx_time);//ÉèÖÃResponse·¢ËÍʱ¼äT3 /* Set expected delay and timeout for final message reception. */ dwt_setrxaftertxdelay(RESP_TX_TO_FINAL_RX_DLY_UUS);//ÉèÖ÷¢ËÍÍê³Éºó¿ªÆô½ÓÊÕÑÓ³Ùʱ¼ä dwt_setrxtimeout(FINAL_RX_TIMEOUT_UUS);//½ÓÊÕ³¬Ê±Ê±¼ä /* Write and send the response message. See NOTE 9 below.*/ memcpy(&tx_resp_msg[11], &dist[TAG_ID], 2); tx_resp_msg[ALL_MSG_SN_IDX] = frame_seq_nb; dwt_writetxdata(sizeof(tx_resp_msg), tx_resp_msg, 0);//дÈë·¢ËÍÊý¾Ý dwt_writetxfctrl(sizeof(tx_resp_msg), 0);//É趨·¢Ëͳ¤¶È dwt_starttx(DWT_START_TX_DELAYED | DWT_RESPONSE_EXPECTED);//ÑÓ³Ù·¢ËÍ£¬µÈ´ý½ÓÊÕ /* We assume that the transmission is achieved correctly, now poll for reception of expected "final" frame or error/timeout. * See NOTE 7 below. */ while (!((status_reg = dwt_read32bitreg(SYS_STATUS_ID)) & (SYS_STATUS_RXFCG | SYS_STATUS_ALL_RX_ERR)))///²»¶Ï²éѯоƬ״ֱ̬µ½½ÓÊճɹ¦»òÕß³öÏÖ´íÎó { }; /* Increment frame sequence number after transmission of the response message (modulo 256). */ frame_seq_nb++; if (status_reg & SYS_STATUS_RXFCG)//½ÓÊճɹ¦ { /* Clear good RX frame event and TX frame sent in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_RXFCG | SYS_STATUS_TXFRS);//Çå³þ±ê־λ /* A frame has been received, read it into the local buffer. */ frame_len = dwt_read32bitreg(RX_FINFO_ID) & RX_FINFO_RXFLEN_MASK;//Êý¾Ý³¤¶È dwt_readrxdata(rx_buffer, frame_len, 0);//¶ÁÈ¡½ÓÊÕÊý¾Ý /* Check that the frame is a final message sent by "DS TWR initiator" example. * As the sequence number field of the frame is not used in this example, it can be zeroed to ease the validation of the frame. */ rx_buffer[ALL_MSG_SN_IDX] = 0; if (rx_buffer[9] == 0x23) //ÅжÏÊÇ·ñΪFianl°ü { uint32 poll_tx_ts, resp_rx_ts, final_tx_ts; uint32 poll_rx_ts_32, resp_tx_ts_32, final_rx_ts_32; double Ra, Rb, Da, Db; int64 tof_dtu; /* Retrieve response transmission and final reception timestamps. */ resp_tx_ts = get_tx_timestamp_u64();//»ñµÃresponse·¢ËÍʱ¼äT3 final_rx_ts = get_rx_timestamp_u64();//»ñµÃfinal½ÓÊÕʱ¼äT6 /* Get timestamps embedded in the final message. */ final_msg_get_ts(&rx_buffer[FINAL_MSG_POLL_TX_TS_IDX], &poll_tx_ts);//´Ó½ÓÊÕÊý¾ÝÖжÁÈ¡T1£¬T4£¬T5 final_msg_get_ts(&rx_buffer[FINAL_MSG_RESP_RX_TS_IDX], &resp_rx_ts); final_msg_get_ts(&rx_buffer[FINAL_MSG_FINAL_TX_TS_IDX], &final_tx_ts); /* Compute time of flight. 32-bit subtractions give correct answers even if clock has wrapped. See NOTE 10 below. */ poll_rx_ts_32 = (uint32)poll_rx_ts;//ʹÓÃ32λÊý¾Ý¼ÆËã resp_tx_ts_32 = (uint32)resp_tx_ts; final_rx_ts_32 = (uint32)final_rx_ts; Ra = (double)(resp_rx_ts - poll_tx_ts);//Tround1 = T4 - T1 Rb = (double)(final_rx_ts_32 - resp_tx_ts_32);//Tround2 = T6 - T3 Da = (double)(final_tx_ts - resp_rx_ts);//Treply2 = T5 - T4 Db = (double)(resp_tx_ts_32 - poll_rx_ts_32);//Treply1 = T3 - T2 tof_dtu = (int64)((Ra * Rb - Da * Db) / (Ra + Rb + Da + Db));//¼ÆË㹫ʽ tof = tof_dtu * DWT_TIME_UNITS; distance = tof * SPEED_OF_LIGHT;//¾àÀë=¹âËÙ*·ÉÐÐʱ¼ä dist2 = distance - dwt_getrangebias(config.chan, (float)distance, config.prf); //¾àÀë¼õÈ¥½ÃÕýϵÊý dis = dist2 * 100; //dis Ϊµ¥Î»ÎªcmµÄ¾àÀë dist[TAG_ID] = LP(dis, TAG_ID); //LP ΪµÍͨÂ˲¨Æ÷£¬ÈÃÊý¾Ý¸üÎȶ¨ // time32_reset = 0; GPIO_Toggle(GPIOA, LED_PIN); if (GPIO_ReadInputDataBit(GPIOA, SW2) != RESET) //ͨ¹ý²¦Â뿪¹ØÅжÏÊý¾ÝÊä³ö¸ñʽ { dID = TAG_ID; printf("TAG_ID: %2.0f ", dID); dID = ANCHOR_ID; printf("ANCHOR_ID: %2.0f ", dID); printf("Distance: %5.0f cm\n", (double)dist[TAG_ID]); } else { send[2] = ANCHOR_ID; send[3] = TAG_ID; memcpy(&send[4], &dist[TAG_ID], 2); check = Checksum_u16(&send[2], 6); memcpy(&send[8], &check, 2); USART_puts(send, 10); } } } else { /* Clear RX error events in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_ALL_RX_ERR); } } } else { /* Clear RX error events in the DW1000 status register. */ dwt_write32bitreg(SYS_STATUS_ID, SYS_STATUS_ALL_RX_ERR); } } } } /*! ------------------------------------------------------------------------------------------------------------------ * @fn get_tx_timestamp_u64() * * @brief Get the TX time-stamp in a 64-bit variable. * /!\ This function assumes that length of time-stamps is 40 bits, for both TX and RX! * * @param none * * @return 64-bit value of the read time-stamp. */ static uint64 get_tx_timestamp_u64(void) { uint8 ts_tab[5]; uint64 ts = 0; int i; dwt_readtxtimestamp(ts_tab); for (i = 4; i >= 0; i--) { ts <<= 8; ts |= ts_tab[i]; } return ts; } /*! ------------------------------------------------------------------------------------------------------------------ * @fn get_rx_timestamp_u64() * * @brief Get the RX time-stamp in a 64-bit variable. * /!\ This function assumes that length of time-stamps is 40 bits, for both TX and RX! * * @param none * * @return 64-bit value of the read time-stamp. */ static uint64 get_rx_timestamp_u64(void) { uint8 ts_tab[5]; uint64 ts = 0; int i; dwt_readrxtimestamp(ts_tab); for (i = 4; i >= 0; i--) { ts <<= 8; ts |= ts_tab[i]; } return ts; } /*! ------------------------------------------------------------------------------------------------------------------ * @fn final_msg_set_ts() * * @brief Fill a given timestamp field in the final message with the given value. In the timestamp fields of the final * message, the least significant byte is at the lower address. * * @param ts_field pointer on the first byte of the timestamp field to fill * ts timestamp value * * @return none */ static void final_msg_set_ts(uint8 *ts_field, uint64 ts) { int i; for (i = 0; i < FINAL_MSG_TS_LEN; i++) { ts_field[i] = (uint8) ts; ts >>= 8; } } /***************************************************************************************************************************************************** * NOTES: * * 1. The sum of the values is the TX to RX antenna delay, experimentally determined by a calibration process. Here we use a hard coded typical value * but, in a real application, each device should have its own antenna delay properly calibrated to get the best possible precision when performing * range measurements. * 2. The messages here are similar to those used in the DecaRanging ARM application (shipped with EVK1000 kit). They comply with the IEEE * 802.15.4 standard MAC data frame encoding and they are following the ISO/IEC:24730-62:2013 standard. The messages used are: * - a poll message sent by the initiator to trigger the ranging exchange. * - a response message sent by the responder allowing the initiator to go on with the process * - a final message sent by the initiator to complete the exchange and provide all information needed by the responder to compute the * time-of-flight (distance) estimate. * The first 10 bytes of those frame are common and are composed of the following fields: * - byte 0/1: frame control (0x8841 to indicate a data frame using 16-bit addressing). * - byte 2: sequence number, incremented for each new frame. * - byte 3/4: PAN TAG_ID (0xDECA). * - byte 5/6: destination address, see NOTE 3 below. * - byte 7/8: source address, see NOTE 3 below. * - byte 9: function code (specific values to indicate which message it is in the ranging process). * The remaining bytes are specific to each message as follows: * Poll message: * - no more data * Response message: * - byte 10: activity code (0x02 to tell the initiator to go on with the ranging exchange). * - byte 11/12: activity parameter, not used here for activity code 0x02. * Final message: * - byte 10 -> 13: poll message transmission timestamp. * - byte 14 -> 17: response message reception timestamp. * - byte 18 -> 21: final message transmission timestamp. * All messages end with a 2-byte checksum automatically set by DW1000. * 3. Source and destination addresses are hard coded constants in this example to keep it simple but for a real product every device should have a * unique TAG_ID. Here, 16-bit addressing is used to keep the messages as short as possible but, in an actual application, this should be done only * after an exchange of specific messages used to define those short addresses for each device participating to the ranging exchange. * 4. Delays between frames have been chosen here to ensure proper synchronisation of transmission and reception of the frames between the initiator * and the responder and to ensure a correct accuracy of the computed distance. The user is referred to DecaRanging ARM Source Code Guide for more * details about the timings involved in the ranging process. * 5. This timeout is for complete reception of a frame, i.e. timeout duration must take into account the length of the expected frame. Here the value * is arbitrary but chosen large enough to make sure that there is enough time to receive the complete response frame sent by the responder at the * 110k data rate used (around 3 ms). * 6. In a real application, for optimum performance within regulatory limits, it may be necessary to set TX pulse bandwidth and TX power, (using * the dwt_configuretxrf API call) to per device calibrated values saved in the target system or the DW1000 OTP memory. * 7. dwt_writetxdata() takes the full size of the message as a parameter but only copies (size - 2) bytes as the check-sum at the end of the frame is * automatically appended by the DW1000. This means that our variable could be two bytes shorter without losing any data (but the sizeof would not * work anymore then as we would still have to indicate the full length of the frame to dwt_writetxdata()). It is also to be noted that, when using * delayed send, the time set for transmission must be far enough in the future so that the DW1000 IC has the time to process and start the * transmission of the frame at the wanted time. If the transmission command is issued too late compared to when the frame is supposed to be sent, * this is indicated by an error code returned by dwt_starttx() API call. Here it is not tested, as the values of the delays between frames have * been carefully defined to avoid this situation. * 8. We use polled mode of operation here to keep the example as simple as possible but all status events can be used to generate interrupts. Please * refer to DW1000 User Manual for more details on "interrupts". It is also to be noted that STATUS register is 5 bytes long but, as the event we * use are all in the first bytes of the register, we can use the simple dwt_read32bitreg() API call to access it instead of reading the whole 5 * bytes. * 9. As we want to send final TX timestamp in the final message, we have to compute it in advance instead of relying on the reading of DW1000 * register. Timestamps and delayed transmission time are both expressed in device time units so we just have to add the desired response delay to * response RX timestamp to get final transmission time. The delayed transmission time resolution is 512 device time units which means that the * lower 9 bits of the obtained value must be zeroed. This also allows to encode the 40-bit value in a 32-bit words by shifting the all-zero lower * 8 bits. * 10. In this operation, the high order byte of each 40-bit timestamps is discarded. This is acceptable as those time-stamps are not separated by * more than 2**32 device time units (which is around 67 ms) which means that the calculation of the round-trip delays (needed in the * time-of-flight computation) can be handled by a 32-bit subtraction. * 11. The user is referred to DecaRanging ARM application (distributed with EVK1000 product) for additional practical example of usage, and to the * DW1000 API Guide for more details on the DW1000 driver functions. ****************************************************************************************************************************************************/