Commit 0913809d authored by spookysys's avatar spookysys
Browse files

lf dag 2

parent 0cbb0c29

Session2-LF/PWM-LF.c

+37 −7
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ int main(void) 
	//Set LED pins as output

	PORTB.DIRSET = (1 << LED1) | (1 << LED2) | (1 << LED3);

	

	//Because the LEDs are active low, we invert the output

	//Because the LEDs are active low, we invert the output. This means high PWM value -> bright led

	PORTB.PIN0CTRL |= (1 << PORT_INVEN_bp);

	PORTB.PIN1CTRL |= (1 << PORT_INVEN_bp);

	PORTB.PIN4CTRL |= (1 << PORT_INVEN_bp);
@@ -38,19 +38,48 @@ int main(void) 
	PORTA.PIN6CTRL |= (1 << PORT_PULLUPEN_bp);

	PORTA.PIN7CTRL |= (1 << PORT_PULLUPEN_bp);	

	

	//Set clock prescaler div256

	TCA0.SINGLE.CTRLA |= (TCA_SINGLE_ENABLE_bm); //Enable timer

	TCA0.SINGLE.CTRLB |= (0x05 << TCA_SINGLE_WGMODE0_bp); //Set mode to single slope

	/*We will be using timer 1 in single (not split) mode.

	  It is highly recommended that you read chapter 20.3.3.4 in the datasheet 

	  on timer compare channels.

	  There you will find a sub-capter on the single-slope PWM we will be using.

	*/

	

	//First, enable the timer

	TCA0.SINGLE.CTRLA |= (TCA_SINGLE_ENABLE_bm); 

	

	//Set the mode of the timer to single slope PWM

	TCA0.SINGLE.CTRLB |= (0x03 << TCA_SINGLE_WGMODE0_bp);

	

	TCA0.SINGLE.CTRLB |= (TCA_SINGLE_CMP0EN_bm) | (TCA_SINGLE_CMP1EN_bm); //Enable the compare channels

	//We have to override the normal pin opperation so the PWM is pushed directly to the pin

	//Hint: WO0 and WO1 are connected to leds. We need to override them to get the PWM out.

	TCA0.SINGLE.CTRLB |= (TCA_SINGLE_CMP0EN_bm) | (TCA_SINGLE_CMP1EN_bm);

	

	/*Timer A is a 16 bit timer. This will give us a frequency of 25Hz, we can see it flicker.

	  By lowering the period, (PER) we get higher frequency at the cost of lower resolution.

	*/

	

	//Set the period to 12 bit. (This results in a frequency of ~400Hz.)

	TCA0.SINGLE.PER = 0x0fff; //We set our top to have a sufficiently high frequency (Top at 16 bit (0xffff) ~25Hz, 12 bit (0x0fff) ~400Hz)

	TCA0.SINGLE.CMP0 = 0x0000;

	TCA0.SINGLE.CMP1 = 0x0fff;

	

	//We can now control the PWM duty cycle by simply writing values to the CMP0 and CMP1 registers.

	TCA0.SINGLE.CMP0 = 0x0000; //We have inverted the pin outputs so this is MIN

	TCA0.SINGLE.CMP1 = 0x0fff;	//We have inverted the pin outputs so this is MAX

	

	

    while(1){

		

		/*Have some fun with the leds. Examples:

		  Have them fade between max and min

		  Have them fade in a pattern (Heartbeat?) 

		  Change the brightness based on buttons



		*/

		

		//Here we use button pushes to shift the CMP register so we get brightness steps

		//adding and subtracting works just as well

		

		//It is largely up to the student to choose how the led brightness is changed.

		

		if (!(PORTA.IN & (1 << SW1))){

			if(!SW1_pressed){

				TCA0.SINGLE.CMP0 = (((TCA0.SINGLE.CMP0 << 1) + 1) & (0x0fff)); //Shift in a 1, and cut off excess to 12 bit
@@ -63,6 +92,7 @@ int main(void) 
			SW1_pressed = false;

		}

		

		

		if (!(PORTA_IN & (1 << SW2))){

			if(!SW2_pressed){

				TCA0.SINGLE.CMP1 = (((TCA0.SINGLE.CMP1 << 1) + 1) & (0x0fff)); //Shift in a 1, and cut off excess to 12 bit

Session2-LF/TIMER-LF.c

+20 −8
Original line number Diff line number Diff line
@@ -12,8 +12,8 @@ 
#include <util/delay.h>

#include <avr/interrupt.h>



#define LED1 0 // port B, connected to WO0

#define LED2 1 // port B, connected to WO1

#define LED1 0 // port B

#define LED2 1 // port B

#define LED3 4 // Port B
@@ -24,14 +24,24 @@ int main(void) 
	*/



	PORTB.DIR = (1 << LED1) | (1 << LED2);

	PORTB.OUTTGL = (1 << LED1); //Only to start with LEDs off	

	PORTB.OUTTGL = (1 << LED1); //Starting with only 1 LED on	

	

	//We will be using a timer overflow interupt with timer A

	//We set the prescaler to clk=clk/256

	/*We will be using timer A that will trigger an overflow interupt.

	  This is a 16 bit timer that can run in 2 modes

		-single mode as 1 16-bit timer

		-dual/split mode as 2 8-bit timers

	  We will be using single mode in this exercise.

	  

	  Hint because the register names can be hard to understand:

	  TCA0.SINGLE.CTRLA addresses the control A register for timer A

	  

	  First we set the prescaler to clk=clk/256 and enable the timer. 

	  This is done by setting the right bits in the control A register.

	*/

	TCA0.SINGLE.CTRLA |= (TCA_SINGLE_CLKSEL_DIV256_gc) | (TCA_SINGLE_ENABLE_bm);

	



	//Next we Enable timer interupts on overflow 

	//Next we Enable timer interupts on overflow on timer A

	TCA0.SINGLE.INTCTRL |= (TCA_SINGLE_OVF_bm);

	

	//Finally we have to set the max value of the timer, the top.
@@ -50,9 +60,11 @@ int main(void) 
}



ISR(TCA0_OVF_vect){



	//Do something with the led(s), like toggle.

	PORTB.OUTTGL = (1 << LED1) | (1 << LED2);

	

	TCA0.SINGLE.INTFLAGS = ( TCA_SINGLE_OVF_bm); //Clear the interupt flag

	//Clear the interrupt flag.

	//If we do not clear the flag, we will instantly jump back into the ISR again

	TCA0.SINGLE.INTFLAGS = ( TCA_SINGLE_OVF_bm);

	

}
 
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Session2-LF/UART-LF.c

+28 −8
Original line number Diff line number Diff line
@@ -12,42 +12,61 @@ 
#include <avr/interrupt.h>

#include <util/delay.h>



/*

In this exercise we will set up and use UART communication.

The embedded debugger has a virtual com port that we will use to communicate with the computer.



*/





void uart_init(unsigned long baud){

	

	//From chapter 24.3 in datasheet

	PORTB.OUTSET = (1 << PIN2_bp); 

	PORTB.DIRSET = (1 << PIN2_bp); 	//Setting up TX pin as output

	USART0.BAUDH = (baud >> 8); 	//Shift register right by 8 bits

	USART0.BAUDL = baud; 			//Set baud rate

	PORTB.OUTSET = (1 << PIN2_bp); 	//Setting the TX pin high

	

	USART0.BAUDH = (baud >> 8); 	//Shift register right by 8 bits to get the 8 high bits

	USART0.BAUDL = baud; 			//Set baud rate without shifting to get the 8 low bits

	

	//It turns out the compiler can handle this automatically, meaning this works just as well:

	//USART0.BAUD = baud;

	

	

	//USART.CTRLC CMODE bits default to async, 1 stop bit, 8 bit character size

	

	USART0.CTRLB |= (1 << USART_RXEN_bp) | (1 << USART_TXEN_bp);	//Enable RX and TX



	USART0.CTRLA |= (1 << USART_RXCIE_bp); //Enable interrupts on incomming data

	USART0.CTRLA |= (1 << USART_RXCIE_bp); //Enable interrupts on incoming data

}



// function to transmit data

void uart_transmit(unsigned char data){

	

	//In this function we will be send data.

	

	//First we should check that there isn't already data being sent

	//	if there is, we should probably wait for it to finish first

	while (!(USART0.STATUS & (1 << USART_DREIF_bp))){

		//wait for previous transmit to finish

	};

	

	//Put our new data into se sending register

	USART0.TXDATAL = data;

}





int main(void)

{

	//Initialize the UART with our function. 

	//We will be using a baudrate of 9600 (defined as BAUD_9600 at the top of the file)

	uart_init(BAUD_9600);

	

	uart_init(BAUD_9600); //start uart with baudrate of 9600

	

	sei(); //Important for anything here to work

	sei(); //Enable inerrupt, important for anything here to work

	

    while (1) 

    {

		//Do nothing, interrupts handle everything

		//We don't really need to do anything here.

		//the ISR will handle receiving. 

    }

}
@@ -55,6 +74,7 @@ int main(void) 
//Interrupt service routine for the receiver.

ISR(USART0_RXC_vect){

	

	//Read out the received data to a variable

	uint8_t data = USART0_RXDATAL;

	//Do things with data:

	uart_transmit(data + 1); //Example: Shift all characters by one step A -> B, B -> C etc.

Session2/Timer/main.c

+3 −3
Original line number Diff line number Diff line
@@ -22,12 +22,12 @@ int main(void) 
	

	/*We will be using timer A that will trigger an overflow interupt.

	  This is a 16 bit timer that can run in 2 modes

		-sigle mode as 1 16-bit timer

		-single mode as 1 16-bit timer

		-dual/split mode as 2 8-bit timers

	  We will be using single mode in this exercise.

	  

	  Hint because the register names can be hard to understand:

	  TCA0.SINGLE.CTRLA adresses the control A register for timer A

	  TCA0.SINGLE.CTRLA addresses the control A register for timer A

	  

	  First we set the prescaler to clk=clk/256 and enable the timer. 

	  This is done by setting the right bits in the control A register.
@@ -58,7 +58,7 @@ ISR(TCA0_OVF_vect){ 


	//Do something with the led(s), like toggle.

	

	//Clear the interupt flag.

	//Clear the interrupt flag.

	//If we do not clear the flag, we will instantly jump back into the ISR again

	

}
 
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Session2/UART/.gitignore

deleted100644 → 0
+0 −2
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UART/Debug

.vs