changed the serial protocol and cleaned up the code, fixed a bug in the timer (PWM got inverted sometimes)

schaltungen/displayboard_servo/software/src/main.c

@@ -12,113 +12,77 @@
 #define POWER_MAX	400
 #define SERVO_STEPS	125
 
-#define BUFSIZE		32
+#define BUFSIZE		10
 
 volatile uint16_t syscounter = 0;
-
+volatile uint16_t power;
-// values send over uart from powerboard
-typedef struct {
-	uint16_t voltage_gen;
-	uint16_t voltage_reg;
-	uint16_t current_gen;
-	
-	struct {
-		uint8_t loadsw : 1;
-		uint8_t gensw : 1;
-		uint8_t batsw : 1;
-	};
-} PWR_DATA;
-
-static PWR_DATA pd;
 uint8_t data_count = 0;
 char data_in[BUFSIZE];
 
+   
 void reset_input_buffer(void) {
 	data_count = 0;
 	memset(data_in, 0, BUFSIZE);
 }
    
-static void update_servo_position() {
-	uint32_t power;
-	power = ( (pd.voltage_gen / 100) * (pd.current_gen / 100) ) / 100;      
-	set_servo(power & 0xffff); 
-}
-   
 static void timer_init(void) {
 	// CTC Mode for Timer 1 (16Bit) with prescale of 64
 	TCCR1B |= _BV(WGM12) | _BV(CS11) | _BV(CS10);       
 	OCR1A = 2250;           // set Servo to max. position
 	TIMSK |= _BV(OCIE1A);	// enable timer interrupt
-	TCCR1A |= (1<<COM1A0);   // toggle OCR1A on overflow
+	TCCR1A |= _BV(COM1A0);   // toggle OCR1A on overflow
+    
+    // CTC Mode for Timer 0 (8Bit) with prescale of 1024
+    TCCR0B |= _BV(CS02) | _BV(CS00);    // prescaler
+    TCCR0A |= _BV(WGM01);   // CTC mode
+    TIMSK |= _BV(OCIE0A);   // enable timer interrupt
+    
+    OCR0A = 78; // gives us ~100ms interval
 }
 
 static void ports_init(void) {
 	DDRB |= _BV(PB3); 
 }
 
-static void process_command(char *command) {
-	if(command[0] == 'A') {
-		// command must be in the following format:
-		// A$voltage_gen,$voltage_reg,$current_gen,loadsw,batsw,gensw\n
-		// examples: 
-		//	A24500,13400,12000,1,1,1B
-		//	A19900,11000,15000,1,1,1B
-		//	A20000,12300,10000,1,1,1B
-
-		char *token;
-		uint8_t tokencounter = 0;
-
-		token = strtok(command, ","); 
-
-		while( token ) {
-			switch(tokencounter) {
-				case 0:
-					// skip the A in front of the number
-					pd.voltage_gen = atoi(++token);
-					break;
-				case 1:
-					pd.voltage_reg = atoi(token);
-					break;
-				case 2:
-					pd.current_gen = atoi(token);
-					break;
-				case 3:
-					if(atoi(token) == 1) pd.loadsw = 1;
-					else pd.loadsw = 0;
-					break;
-				case 4:
-					if(atoi(token) == 1) pd.batsw = 1;
-					else pd.batsw = 0;
-					break;
-				case 5:
-					if(atoi(token) == 1) pd.gensw = 1;
-					else pd.gensw = 0;
-					break;
-			}
-			
-			tokencounter++;
-			token = strtok(NULL, ",");
-		}
-
-		update_servo_position();        
-	}
-}
-
 static void work_uart() {
 	uint16_t c = uart_getc();
 
 	if ( !(c & UART_NO_DATA) ) {
-		data_in[data_count] = (c & 0xff);
+        char cur = c & 0xff;
         
-		if (data_in[data_count] == 'B') {
+		data_in[data_count] = cur;
-			process_command(data_in);    
+        //uart_print_uint8(cur);
-			reset_input_buffer();
-		} 
         
         data_count++;
 		if(data_count >= BUFSIZE) {	// buffer overflow
 			reset_input_buffer();
 		}
+        
+#ifdef DEBUG
+        for(uint8_t i=0;i<BUFSIZE;i++) {
+            uart_print_uint8(data_in[i]);
+            uart_putc('\r');
+            uart_putc('\n');
+        }
+        uart_puts_P(" -- \r\n");
+#endif
+
+		if (cur == '\n' && data_count > 1) { // \n
+			
+            power = atol(data_in);
+            if(power > POWER_MAX) power = POWER_MAX;
+
+#ifdef DEBUG
+            uart_puts_P("power = ");
+            uart_print_uint16(power);
+            uart_puts_P("\r\n");
+
+#endif
+
+            set_servo(power);
+           
+			reset_input_buffer();
+		} 
 	}
 }
 
@@ -129,34 +93,40 @@ static void work_uart() {
  */
 void set_servo(uint16_t display) {
 
-	if( display < 1 ) display = POWER_MIN;
 	if( display > POWER_MAX ) display = POWER_MAX;
 
 	display = POWER_MAX-display;        // invert the value / servo
 
 	display = display * 10;				// *10 otherwise we need float
-	display = display / ( (POWER_MAX*10) / SERVO_STEPS );
+	display = display / ((POWER_MAX * 10) / SERVO_STEPS);
 	display = display + SERVO_STEPS;
 
+#ifdef DEBUG
 	uart_puts_P("display = ");
 	uart_print_uint16(display);
 	uart_puts_P("\r\n");
-
+#endif
-	//cli();								// read and write atomic
-	TIMSK &= ~_BV(OCIE1A);
 
     if( display < 125 ) display = 125;	// just make sure, the timer
 	if( display > 250 ) display = 250;  // is never out ouf 20ms grid
-	OCR1A = 2500-display;
 
-	TIMSK |= _BV(OCIE1A);
+    
+    // check if timer is currently in the small pulse, then sleep here 2ms
+    // and do again
+    if(OCR1A < 2250) {
+        _delay_ms(2);
+    }
+
+	cli();								// read and write atomic
+	OCR1A = 2500-display;
+    sei();
 }
 
 
 /**
  * \brief	the method moves the servo one complete cycle
  */
-void demo_display(void) {
+static void demo_display(void) {
 	set_servo(0);
 	wait(100);
 	set_servo(400);
@@ -179,12 +149,17 @@ int main(void) {
 	while(1) {
 		work_uart();
 
-		if((syscounter % 25) == 0) {	// about every 500ms
+		if(syscounter >= 100) {
 			reset_input_buffer();
 			uart_putc('a'); 	// send a to receive values from master box
-		}
+            syscounter = 0;
             
-		syscounter %= 1000;
+#ifdef DEBUG 
+            uart_puts_P("OCR1A = ");
+            uart_print_uint16(OCR1A);
+            uart_puts_P("\r\n");
+#endif
+		}
 	}
 	
 	return(0);
@@ -195,10 +170,11 @@ int main(void) {
  * 			the system clock varies a bit, but this does not matter
  */
 ISR(TIMER1_COMPA_vect) {
-	syscounter++;
 	OCR1A = 2500-OCR1A;	// Das Servosignal wird aus der Differenz von
 						// Periodenlänge (2500*0,008ms=20ms) und letztem
 						// Vergleichswert (OCR1A) gebildet	
 }
 
-
+ISR(TIMER0_COMPA_vect) {
+    syscounter++;
+}

schaltungen/displayboard_servo/software/src/utils.c

@@ -47,5 +47,10 @@ void uart_print_uint16(uint16_t x) {
     uart_putc(48 + (x % 100 / 10 ));
     uart_putc(48 + (x % 10));
 }
+void uart_print_uint8(uint8_t x) {
+    uart_putc(48 + (x % 1000 / 100 ));
+    uart_putc(48 + (x % 100 / 10 ));
+    uart_putc(48 + (x % 10));
+}
 
 

schaltungen/displayboard_servo/tester.py

@@ -6,30 +6,32 @@ import time
 
 ser = serial.Serial("/dev/ttyUSB0", 38400)
 
-voltage = 20000
+power = 0
-current = 0
 incdec = 0
 
 while 1:
 	tdata = ser.read()
 	time.sleep(1)
-	data_left = ser.inWaiting()
-	tdata += ser.read(data_left)
 
-	out = "A%05d,12300,%05d,1,1,1B" % (voltage, current)
+	if tdata == 'a':
-	print out
+		print power
-	ser.write(out)
+		ser.write(str(power) + '\n')
+		#ser.write('100\n')
+		ser.flush()
 
 		if incdec == 0:
-		current = current + 1000
+			power = power + 10
 		else:
-		current = current - 1000
+			power = power - 10
 		
-	if current > 20000:
+		if power > 400:
-		current = 20000
+			power = 400
 			incdec = 1
 		
-	if current < 0:
+		if power < 0:
-		current = 0
+			power = 0
 			incdec = 0
-		
+	else:
+		data_left = ser.inWaiting()
+		tdata += ser.read(data_left)
+		print tdata