RX/TX and system timestamp handling

DW1000-arduino-test/DW1000-arduino-sender-test/DW1000-arduino-sender-test.ino

@@ -16,7 +16,8 @@
 
 // DEBUG packet sent status and count
 volatile boolean sent = false;
-volatile int numSent = 0;
+int sentNum = 0;
+unsigned long sentTime = 0;
 // reset line to the chip
 int RST = 9;
 // chip driver instances with chip select and reset
@@ -56,23 +57,32 @@ void serviceIRQ() {
   }
   // "NOP" ISR
   sent = true;
-  numSent++;
 }
 
 void loop() {
-  // transmit some data
-  Serial.print("Transmitting packet ... #"); Serial.println(numSent+1);
-  dw.newTransmit();
-  dw.setDefaults();
-  String msg = "Hello DW1000";
-  dw.setData(msg);
-  dw.startTransmit();
-  // enter on confirmation of ISR status change (successfully sent)
   if(sent) {
-    Serial.print("Processed packet ... #"); Serial.println(numSent);
+    // process confirmation of ISR status change (successfully sent)
     sent = false;
+    if(!dw.isTransmitDone()) {
+      return;    
+    }
+    // update and print some information about the sent message
+    unsigned long newSentTime = dw.getTransmitTimestamp();
+    Serial.print("Processed packet ... #"); Serial.println(sentNum);
+    Serial.print("Sent timestamp ... "); Serial.println(newSentTime);
+    // NOTE: delta is just for simple demo as not correct on system time counter wrap-around
+    Serial.print("Delta send time [s] ... "); Serial.println((newSentTime - sentTime) * 1e-9 * 8.01282);
+    sentTime = newSentTime;
+    sentNum++;
+  } else {
+    // transmit some data
+    Serial.print("Transmitting packet ... #"); Serial.println(sentNum);
+    dw.newTransmit();
+    dw.setDefaults();
+    String msg = "Hello DW1000";
+    dw.setData(msg);
+    dw.startTransmit();
+    // wait a bit
+    delay(500);
   }
-  // wait a bit
-  delay(500);
-  //Serial.println(dw.getPrettyBytes(SYS_STATUS, NO_SUB, LEN_SYS_STATUS));
 }

DW1000/DW1000.cpp

@@ -42,10 +42,7 @@ DW1000::~DW1000() {
 
 void DW1000::initialize() {
 	// reset chip
-	digitalWrite(_rst, LOW);
-	delay(10);
-	digitalWrite(_rst, HIGH);
-	delay(10);
+	reset();
 	// default network and node id
 	writeValueToBytes(_networkAndAddress, 0xFF, LEN_PANADR);
 	writeNetworkIdAndDeviceAddress();
@@ -71,6 +68,13 @@ void DW1000::initialize() {
 	delay(10);
 }
 
+void DW1000::reset() {
+	digitalWrite(_rst, LOW);
+	delay(10);
+	digitalWrite(_rst, HIGH);
+	delay(10);
+}
+
 void DW1000::tune() {
 	// re-tune chip for channel 5 (default)
 	byte agctune1[LEN_AGC_TUNE1];
@@ -261,7 +265,7 @@ boolean DW1000::isSuppressFrameCheck() {
 	return getBit(_sysctrl, LEN_SYS_CTRL, SFCST_BIT);
 }
 
-void DW1000::delayedTransceive(unsigned int delayNanos) {
+void DW1000::delayedTransceive(unsigned long delayNanos) {
 	if(_deviceMode == TX_MODE) {
 		setBit(_sysctrl, LEN_SYS_CTRL, TXDLYS_BIT, true);
 	} else if(_deviceMode == RX_MODE) {
@@ -270,6 +274,7 @@ void DW1000::delayedTransceive(unsigned int delayNanos) {
 		// in idle, ignore
 		return;
 	}
+	byte delayBytes[5];
 	// TODO impl 40 bit in DX_TIME register, 9 lower sig. bits are ignored
 }
 
@@ -431,6 +436,32 @@ void DW1000::getData(String& data) {
 	free(dataBytes);
 }
 
+unsigned long DW1000::getTransmitTimestamp() {
+	byte txTimeBytes[LEN_TX_STAMP];
+	readBytes(TX_TIME, TX_STAMP_SUB, txTimeBytes, LEN_TX_STAMP);
+	return getTimestampAsLong(txTimeBytes+1);
+}
+
+unsigned long DW1000::getReceiveTimestamp() {
+	byte rxTimeBytes[LEN_RX_STAMP];
+	readBytes(RX_TIME, RX_STAMP_SUB, rxTimeBytes, LEN_RX_STAMP);
+	return getTimestampAsLong(rxTimeBytes+1);
+}
+
+unsigned long DW1000::getSystemTimestamp() {
+	byte sysTimeBytes[LEN_SYS_TIME];
+	readBytes(SYS_TIME, NO_SUB, sysTimeBytes, LEN_SYS_TIME);
+	return getTimestampAsLong(sysTimeBytes+1);
+}
+
+unsigned long DW1000::getTimestampAsLong(byte ts[]) {
+	unsigned long tsValue = ((unsigned long)ts[0] >> 1);
+	tsValue |= ((unsigned long)ts[1] << 7);
+	tsValue |= ((unsigned long)ts[2] << 15);
+	tsValue |= ((unsigned long)ts[3] << 23);
+	return tsValue;
+}
+
 // system event register
 boolean DW1000::isTransmitDone() {
 	// read whole register and check bit

DW1000/DW1000.h

@@ -75,11 +75,21 @@
 #define SYS_MASK 0x0E
 #define LEN_SYS_MASK 4
 
+// system time counter
+#define SYS_TIME 0x06
+#define LEN_SYS_TIME 5
+
 // RX timestamp register
 #define RX_TIME 0x15
 #define LEN_RX_TIME 14
 #define RX_STAMP_SUB 0
-#define LEN_RX_STAMP_SUB 5
+#define LEN_RX_STAMP 5
+
+// TX timestamp register
+#define TX_TIME 0x17
+#define LEN_TX_TIME 10
+#define TX_STAMP_SUB 0
+#define LEN_TX_STAMP 5
 
 // timing register (for delayed RX/TX)
 #define DX_TIME 0x0A
@@ -191,6 +201,7 @@ class DW1000 {
 	DW1000(int ss, int rst);
 	~DW1000();
 	void initialize();
+	void reset();
 	void tune();
 
 	// device id, address, etc.
@@ -210,7 +221,7 @@ class DW1000 {
 
 	// SYS_CTRL, TX/RX_FCTRL, transmit and receive configuration
 	void suppressFrameCheck(boolean val);
-	void delayedTransceive(unsigned int delayNanos); // TODO impl
+	void delayedTransceive(unsigned long delayNanos); // TODO impl
 	void dataRate(byte rate);
 	void pulseFrequency(byte freq);
 	void preambleLength(byte prealen);
@@ -221,6 +232,9 @@ class DW1000 {
 	void getData(byte data[], int n);
 	void getData(String& data);
 	int getDataLength();
+	unsigned long getTransmitTimestamp();
+	unsigned long getReceiveTimestamp();
+	unsigned long getSystemTimestamp();
 	boolean isSuppressFrameCheck();
 
 	// RX/TX default settings
@@ -335,6 +349,9 @@ class DW1000 {
 	/* writing numeric values to bytes. */
 	void writeValueToBytes(byte data[], int val, int n); 
 
+	/* writing DW1000 timestamp values to unsigned long. */
+	unsigned long getTimestampAsLong(byte ts[]);
+
 	/* internal helper for bit operations on multi-bytes. */
 	boolean getBit(byte data[], int n, int bit);
 	void setBit(byte data[], int n, int bit, boolean val);
@@ -345,6 +362,9 @@ class DW1000 {
 	static const byte WRITE_SUB = 0xC0; // write with sub address
 	static const byte READ = 0x00; // regular read
 	static const byte READ_SUB = 0x40; // read with sub address
+
+	/* Time resolution [ns] of time based registers/values. */
+	static const float TIME_RES = 8.012820513;
 };
 
 #endif