Differences

This shows you the differences between two versions of the page.

--- code:interrupt_driven_tsip [2008/06/17 11:54] – laurenceb
+++ code:interrupt_driven_tsip [2008/10/11 11:28] (current) – laurenceb
@@ Line 2: / Line 2: @@
 //global(s)
 extern gps_type Gps;
 // Interrupt driven TSIP (lassen iq) parser for Atmel AVR (state machine based)
 #define ETX 0x03			//as defined in TSIP specs
 #define DLE 0x10
+//8O1 send routine for initial setup
+int suart_send(char c)
+{
+	u08 n;
+	u08 p=FALSE;		//odd parity
+	CLEAR;				//start bit
+	delay;
+	for(n=0;n<8;n++)		//the data
+	{
+		if(c & 0x01)
+		{
+			SET;		//update parity
+			p=!p;
+		}
+		else
+		{
+			CLEAR;
+		}
+		c>>=1;
+		delay;
+	}
+	if(p)				//the parity
+	{
+		SET;
+	}
+	else
+	{
+		CLEAR;
+	}
+	delay;
+	SET;				//stop bit
+	delay;
+	return 0;
+}
 ISR(USART_RX_vect)			//UART interrupt on mega xx8 series
 {
 	static u08 id;
-	static u08 placemark;
+	static u08 placemarker;
 	static gps_type gps;
-	static u08 *d;
 	static u08 state;		//state machine
+	u08 *d=(u08*)&gps;		//points to our data
 	if(UCSR0A & (BV(FE0)|BV(UPE0)))	//a framing or parity error causes us to drop the packet
 	{
@@ Line 20: / Line 56: @@
 	}
 	char c=UDR0;
-	switch(state)
+	if(state==2 || state==4)				//the two states where we can write something
+	{
+		if(!placemarker && id==0x6D)		//start of packet - the status byte
+		{
+			gps.status= c & 0x0F;		//number from 0 to 7, 0=undefined, 7=ground station,4 3D
+			gps.nosats=(c & 0xF0)>>4;	//number of tracked satellites
+		}
+		else if(id==0x4A)	//lla(time) packet - 4 floats
+		{
+			if(placemarker<12)				//lla
+			{
+				d[27-placemarker]=c;
+			}
+			if(placemarker>15 && placemarker<20)	//time
+			{
+				d[31-placemarker]=c;		//time of fix
+			}
+		}
+		else if(id==0x56 && placemarker<12)  //enu packet - 3 floats
+		{
+			d[11-placemarker]=c;
+		}
+		else if(placemarker>27)				//max 7 floats
+		{
+			state=0;					//we had too much data, something is wrong
+		}
+		placemarker++;					//incr placeholder
+	}
+	switch(state)		//run the state machine
 	{
 		case 0:
@@ Line 35: / Line 99: @@
 			id=c;
 		}
-		else			//unknown or not something we are interested in
+		else					//unknown or not something we are interested in
 		{
 			state=0;
@@ Line 49: / Line 113: @@
 		if(c==ETX)
 		{
-			toggle_pin;			//toggles pin D5 - flashing LED tells us gps is working
+			state=0;				//end of packet - we arent in one
-			if(!Gps.packetflag)		//main has unlocked the data
+			if(id==0x6D)			//the 0x6D packet is sent after a fix calculation or at 1Hz
 			{
-				Gps.packetflag=TRUE;	//this is usually the last interesting part of the fix info to come through
+				gps.packetflag=TRUE;//TRUE==1
-				Gps=gps;		//copy into the global variable
+				toggle_pin;			//toggles pin D5 - flashing LED tells us gps is working
-				VENU=FALSE;		//dont need to run again
+				if(!Gps.packetflag)		//main has unlocked the data
+					{
+						Gps=gps;		//copy into the global variable
+					}
 			}
 		}
@@ Line 61: / Line 128: @@
 			state=4;
 		}
-		else					//this shouldnt happen
+		else						//this shouldnt happen
 		{
 			state=0;
@@ Line 67: / Line 134: @@
 		break;
 		case 4:
-		if(c==ETX || c==DLE)			//state 4 shouldnt get either of these
+		if(c==ETX || c==DLE)		//state 4 shouldnt get either of these
 		{
 			state=0;
 		}
 		break;
-		default:				//something wrong, go to 0
+		default:					//something wrong, go to 0
 		state=0;
-	}
-	if(state==2 || state==4)			//the two states where we can write something
-	{
-		if(!placemarker && id==0x6D)		//the status byte
-		{
-			gps.status= c & 0x07;		//number from 0 to 7, 0=undefined, 7=ground station,4 3D
-		}
-		else if(placemarker<12)			//we only get first 3 floats
-		{
-			if(id==0x4A)
-			{
-				switch(placemarker)	//we copy the UART into ram with memcpy
-				{
-					case 0:
-					d=&gps.latitude;
-					break;
-					case 4:
-					d=&gps.longitude;
-					break;
-					case 8:
-					d=&gps.altitude;
-					break;
-					default:
-				}
-				if(d==&gps.latitude)
-				{
-					memcpy(d+placemarker,&c,1);
-				}
-				if(d==&gps.longitude)
-				{
-					memcpy(d+placemarker-4,&c,1);
-				}
-				if(d==&gps.latitude)
-				{
-					memcpy(d+placemarker-8,&c,1);
-				}
-			}
-			else if(id==0x56)
-			{
-				switch(placemarker)
-				{
-					case 0:
-					d=&gps.veast;
-					break;
-					case 4:
-					d=&gps.vnorth;
-					break;
-					case 8:
-					d=&gps.vup;
-					break;
-					default:
-				}
-				if(d==&gps.veast)
-				{
-					memcpy(d+placemarker,&c,1);
-				}
-				if(d==&gps.vnorth)
-				{
-					memcpy(d+placemarker-4,&c,1);
-				}
-				if(d==&gps.vup)
-				{
-					memcpy(d+placemarker-8,&c,1);
-				}
-			}
-		}
-		else if(placemarker>27)				//max 7 floats
-		{
-			state=0;				//we had too much data, something is wrong
-		}
-		placemarker++;					//incr placeholder
 	}
 }</code>