I honestly cannot figure out what I'm doing wrong here. I have a LED and an oscilloscope probe attached to the LED at port B3, but the output is flat 2V for some reason.
#include <avr/io.h>
#include <avr/interrupt.h>
#define LED 3
void tog(void)
{
PORTB ^= (1 << LED);
}
int main(void)
{
int i = 0;
DDRB |= (1 << LED);
TCCR0A |= (1 << WGM01);
OCR0A = 0xF9;
TIMSK0 |= (1 << OCIE0A);
TCNT0 = 0;
sei();
TCCR0B |= (1 << CS02);
while (1)
{
i++;
}
}
ISR (TIMER0_COMPA_vect)
{
tog();
}
Related
I try to transmit data from my Atmega168A-PU to my computer using the USART.
To do so I have written the following code:
#include <avr/io.h>
#include <stdlib.h>
#define F_CPU 8000000UL
#define USART_BAUD 9600
#define UBRR_VALUE (F_CPU/16/USART_BAUD - 1)
void
usart_init(void)
{
UBRR0H = (unsigned char)(UBRR_VALUE >> 8);
UBRR0L = (unsigned char)UBRR_VALUE;
UCSR0B = _BV(TXEN0) | _BV(UDRIE0);
UCSR0C = _BV(USBS0) | _BV(UCSZ00) | _BV(UCSZ01);
//UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);
}
ISR(USART0_UDRE_vect)
{
UDR0 = '0';
UCSR0A |= _BV(TXC0);
}
int main(void)
{
usart_init();
while(!(UCSR0A & _BV(UDRE0)));
UDR0 = '0';
while(1);
return 0;
}
I have attached the Arduino USB2SERIAL converter to read the values on my computer, however the converter says that he does not receive data and my computer does not receive data either.
Note: My lfuse is 0xe2 (CLKDIV8 disabled), so I have 8MHz F_CPU.
Note: I tried without the UCSR0A |= _BV(TXC0);, too.
Note: I have a capacitor between AVcc and AGnd.
Note: Fuses: (E:F9, H:DF, L:E2)
Well the problem was pretty easy. I forgot the sei(); as #KIIV pointed out (also u/odokemono pointed that out). Thanks.
Also it is better to use the USART_TX_vect instead of USART0_UDRE_vect because my receiver is disabled. Here is the corrected code:
#include <avr/io.h>
#include <stdlib.h>
#include <avr/interrupt.h>
#define F_CPU 8000000UL
#define USART_BAUD 9600
#define UBRR_VALUE (F_CPU/16/USART_BAUD - 1)
void
usart_init(void)
{
UBRR0H = (unsigned char)(UBRR_VALUE >> 8);
UBRR0L = (unsigned char)UBRR_VALUE;
UCSR0B = _BV(TXEN0) | _BV(TXCIE0);
UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);
//UCSR0C = _BV(UCSZ00) | _BV(UCSZ01);
sei();
}
ISR(USART_TX_vect)
{
UDR0 = '0';
UCSR0A |= _BV(TXC0);
}
int main(void)
{
usart_init();
while(!(UCSR0A & _BV(UDRE0)));
UDR0 = '0';
while(1);
return 0;
}
By the way: I disabled the second stop bit as u/odokemono pointed out because my USB2SERIAL seems to work better without the second stop bit.
I have encountered this exercise which asks for which code is faster between the following two.
First code.
int sum = 0;
for(int i = 0; i < n; i++) {
sum += array[i*n + thread_id];
}
Second code.
int sum = 0;
for(int i = 0; i < n; i++) {
sum += array[n*thread_id + i];
}
I would try the code myself I will not have a Nvidia GPU in the following days.
I think that the first code takes advantage of memory coalescing see here, while the second one would take advantage of caching.
Many thanks to #RobertCrovella for clarifying the issues regarding memory coalescing. This is my attempt to benchmark the two codes as asked for. It can be clearly noticed from the output (run on a NVS5400M GPU laptop) that the first code is twice more efficient as compared to the second one. This is because of the memory coalescing taking place in the first one (kernel1).
#include <cuda.h>
#include <ctime>
#include <iostream>
#include <stdio.h>
using namespace std;
#define BLOCK_SIZE 1024
#define GRID_SIZE 1024
// Error Handling
#define gpuErrchk(ans) { gpuAssert((ans), __FILE__, __LINE__); }
inline void gpuAssert(cudaError_t code, const char *file, int line, bool abort=true)
{
if (code != cudaSuccess)
{
fprintf(stderr,"GPUassert: %s %s %d\n", cudaGetErrorString(code), file, line);
if (abort) exit(code);
}
}
//kernel1<<<8,8>>>(d_array,d_sum1,n);
__global__ void kernel1(int *array, long *sum, int n) {
long result=0;
int thread_id=threadIdx.x+blockIdx.x*blockDim.x;
for(int i=0;i<n;i++) {
result += array[i*n + thread_id];
}
//__syncthreads();
sum[thread_id]=result;
}
__global__ void kernel2(int *array, long *sum, int n) {
long result=0;
int thread_id=threadIdx.x+blockIdx.x*blockDim.x;
for(int i=0;i<n;i++) {
result += array[n*thread_id+i];
}
__syncthreads();
sum[thread_id]=result;
}
int main() {
srand((unsigned)time(0));
long *h_sum1,*d_sum1;
long *h_sum2,*d_sum2;
int n=10;
int size1=n*BLOCK_SIZE*GRID_SIZE+n;
int *h_array;
h_array=new int[size1];
h_sum1=new long[size1];
h_sum2=new long[size1];
//random number range
int min =1, max =10;
for(int i=0;i<size1;i++) {
h_array[i]= min + (rand() % static_cast<int>(max - min + 1));
h_sum1[i]=0;
h_sum2[i]=0;
}
int *d_array;
gpuErrchk(cudaMalloc((void**)&d_array,size1*sizeof(int)));
gpuErrchk(cudaMalloc((void**)&d_sum1,size1*sizeof(long)));
cudaEvent_t start, stop;
cudaEventCreate(&start);
cudaEventCreate(&stop);
gpuErrchk(cudaMemcpy(d_array,h_array,size1*sizeof(int),cudaMemcpyHostToDevice));
gpuErrchk(cudaMemcpy(d_sum1,h_sum1,size1*sizeof(long),cudaMemcpyHostToDevice));
cudaEventRecord(start);
kernel1<<<GRID_SIZE,BLOCK_SIZE>>>(d_array,d_sum1,n);
cudaEventRecord(stop);
gpuErrchk(cudaMemcpy(h_sum1,d_sum1,size1*sizeof(long),cudaMemcpyDeviceToHost));
float milliSeconds1=0;
cudaEventElapsedTime(&milliSeconds1,start,stop);
gpuErrchk(cudaMalloc((void**)&d_sum2,size1*sizeof(long)));
gpuErrchk(cudaMemcpy(d_sum2,h_sum2,size1*sizeof(long),cudaMemcpyHostToDevice));
cudaEventRecord(start);
kernel2<<<GRID_SIZE,BLOCK_SIZE>>>(d_array,d_sum2,10);
cudaEventRecord(stop);
gpuErrchk(cudaMemcpy(h_sum2,d_sum2,size1*sizeof(long),cudaMemcpyDeviceToHost));
float milliSeconds2=0;
cudaEventElapsedTime(&milliSeconds2,start,stop);
long result_device1=0,result_host1=0;
long result_device2=0,result_host2=0;
for(int i=0;i<size1;i++) {
result_device1 += h_sum1[i];
result_device2 += h_sum2[i];
}
for(int thread_id=0;thread_id<GRID_SIZE*BLOCK_SIZE;thread_id++)
for(int i=0;i<10;i++) {
result_host1 += h_array[i*10+thread_id];
result_host2 += h_array[10*thread_id+i];
}
cout << "Device result1 = " << result_device1 << endl;
cout << "Host result1 = " << result_host1 << endl;
cout << "Time1 (ms) = " << milliSeconds1 << endl;
cout << "Device result2 = " << result_device2 << endl;
cout << "Host result2 = " << result_host2 << endl;
cout << "Time2 (ms) = " << milliSeconds2 << endl;
gpuErrchk(cudaFree(d_array));
gpuErrchk(cudaFree(d_sum1));
gpuErrchk(cudaFree(d_sum2));
return 0;
}
The Cuda Event timer output is as under:
Device result1 = 57659226
Host result1 = 57659226
Time1 (ms) = 5.21952
Device result2 = 57674257
Host result2 = 57674257
Time2 (ms) = 11.8356
I am using an Attiny 9.
I connected a LED to PB1.
I wrote following code and upload it to the Attiny 9.
#define F_CPU 800000UL
#include <avr/io.h>
#include <util/delay.h>
#include <avr/sleep.h>
#include <avr/power.h>
#define D0 PB1
int main(void)
{
power_adc_disable();
set_sleep_mode(SLEEP_MODE_PWR_DOWN);
TCCR0A |= (1<<WGM00)|(1<<WGM01)|(1<<COM0B1);
TCCR0B |= (1<<WGM03)|(1<<WGM02)|(1<<CS00);
DDRB |= 1<<D0;
PORTB |= 1<<D0;
_delay_ms(3000);
PORTB &= ~(1<<D0);
for (uint8_t i = 255; 247 < i; --i)
{
OCR0B = i;
_delay_ms(70);
}
for (uint8_t i= 247; -1 < i; --i)
{
OCR0B = i;
_delay_ms(4);
}
while(1){
sleep_enable();
sleep_cpu();
}
return 0;
}
I want the LED to be lighten and darken. But after I uploaded the code, the LED illuminates continuously. I also read a datasheet of Attiny 9. I followed how to use PWM. But it's not working.
What's wrong?
There are a number of issues with that code.
You're putting the processor in to power down mode, which according to the datasheet, disables the clocks and only asynchronous events can take place.
You're setting it to use fast PWM mode with OCR0A as your top, but you aren't setting OCR0A anywhere. You won't generate any compare matches if you your timer can't count high enough. It would appear from your loops that you are expecting the timer to count to 255.
You only change the duty cycle of the PWM before your while loop, so even if your PWM gets set up correctly, you won't ever be able to see your LED pulse like you want.
Here's a link giving an example of how to set up a PWM and change its duty cycles:
http://allaboutavr.com/index.php/2017/05/13/chapter-5-timers-and-pwm-pulse-width-modulation/
Ty something like this:
#include <avr/io.h>
#include <util/delay.h>
#define D0 PB1
int main(void)
{
DDRB |= 1<<D0;
TCCR0A |= (1<<WGM00)|(1<<COM0B1);
TCCR0B |= (1<<WGM02)|(1<<CS00);
while (1) {
for (uint8_t i = 0; i < 255; i++) {
OCR0B = i;
_delay_ms(4);
}
for (uint8_t i = 255; i >= 0; i--) {
OCR0B = i;
_delay_ms(4);
}
}
}
i am trying to Read an Voltage Level via a ADC0 of my ATmega8, because of querying a 1 Pin 4x4 Matrix Keypad. The Problem is everytime I apply a Voltage to the ADC higher than GND the Atmega is stopping to do his work. The PWM outputs are still working, but communication via i2c is impossible and the LCD is clear.
My wiring is simple, AREF & AVCC are set to 5V, GND is set to GND and PC0 is my Input. Is there anything I fail to Notice? Thank You for your help.
Here is my Code:
void Initialisierung(void)
{
char text [2];
lcd_init();
cli();
//### TWI
init_twi_slave(SLAVE_ADRESSE); //TWI als Slave mit Adresse slaveadr starten
sei();
lcd_setcursor( 0, 1 );
lcd_string(">Booting...");
lcd_setcursor( 0, 2 );
itoa (SLAVE_ADRESSE,text,16);
lcd_string("I2C Adress=0x");
lcd_string(text);
for (int Index=0; Index<85; ++Index) {
rxbuffer[Index] = 0x20;
}
rxbuffer[81]=0xFF;
rxbuffer[82]=0xFF;
rxbuffer[83]=0xFF;
rxbuffer[84]=0xFF;
}
//update LCD
void lcd_update(void){
for (int o=1;o<=4; o++)
for (int i=1; i<=20; i++){
lcd_setcursor( i-1, o );
lcd_data(rxbuffer[i+((o-1)*20)]);
}
}
An here is the main function:
int main(void)
{
DDRC &= ~(1 << PC0);
PORTC &= ~(1 << PC0);
Initialisierung();
DDRB = (1 << DDB1) | (1 << DDB2);
OCR1A = eeprom_read_word(&brightness); // PWM einstellen,
OCR1B = eeprom_read_word(&contrast);
ICR1 = 1000; // TOP-wert
TCCR1A = (1<<COM1A1) | (1<<COM1B1) | (1<<WGM11); // 2-Kanal "non-inverting"
TCCR1B = (1<<WGM13)|(1<<WGM12) | (1<<CS11);
//Initialize ADC
ADCSRA = (1<<ADEN) | (1<<ADPS2) | (1<<ADPS0);
ADMUX=0x00;
unsigned int adc_value=0; // Variable to hold ADC result
char text[2];
while(1)
{
ADCSRA |= (1<<ADSC); // Start conversion
while (ADCSRA & (1<<ADSC)); // wait for conversion to complete
adc_value = ADCW; //Store ADC value
itoa (adc_value,text,16);
lcd_setcursor( 0,4 );
lcd_string(text);
for (int Index=0; Index<85; ++Index) {
txbuffer[Index] = rxbuffer[Index];
}
uint16_t brightness_i2c=0;
uint16_t contrast_i2c=0;
brightness_i2c=(rxbuffer[81]<<8)|(rxbuffer[82]);
contrast_i2c=(rxbuffer[83]<<8)|(rxbuffer[84]);
if (rxbuffer[0]==1){
lcd_update();
rxbuffer[0]=4;
}else if(brightness_i2c!=eeprom_read_word(&brightness) && brightness_i2c!=0xFFFF){
eeprom_write_word(&brightness,brightness_i2c);
OCR1A = eeprom_read_word(&brightness);
}else if (contrast_i2c!=eeprom_read_word(&contrast) && contrast_i2c!=0xFFFF){
eeprom_write_word(&contrast,contrast_i2c);
OCR1B = eeprom_read_word(&contrast);
}else{
for (uint8_t i=0; i<50; i++) _delay_ms(10);
lcd_setcursor( 19, 4 );
lcd_data(0xFF);
for (uint8_t i=0; i<50; i++) _delay_ms(10);
lcd_setcursor( 19, 4 );
lcd_data(0x20);
}
}
}
I finally got it:
I setup the ADC with interrupts but not freerunning:
ADCSRA =(1<<ADEN)|(1<<ADPS2)|(1<<ADPS1)|(1<<ADIE)| (1<<ADPS0);
And call the ADC everytime at the end of my While loop:
ADCSRA |= (1<<ADSC);
Here is the Code for the ISR:
ISR(ADC_vect)
{
char text[5];
itoa (ADC,text,16);
lcd_setcursor( 0,4 );
lcd_string(text);
}
Thanks for your time ;)
I have written a pwm code for Atmega128. I am using fast pwm mode with non-inverting pulse on compare match and I need to change the OCR0 value at certain times. Yet it doesn't change. Anyone knows what is the problem here ??
#include <avr/interrupt.h>
#include <avr/io.h>
uint8_t tick_1sec;
void timer1_init(void) // 1 second timer
{
OCR1A = 15624;
TIMSK |= (1<<OCIE1A);
TCCR1B = (1<<WGM12); //CTC mode
TCCR1B |= (1<<CS12)|(0<<CS11)|(1<<CS10);
}
ISR(TIMER1_COMPA_vect) //1 second interrupt
{
cli();
tick_1sec = 1;
sei();
}
void timer0_init(void) // fast pwm with OC0 non-inverting mode
{
TCCR0 = (1<<FOC0)|(1<<WGM01)|(1<<WGM00);
TCCR0 |= (1<<COM01)|(0<<COM00);
TCCR0 |= (1<<CS02)|(1<<CS01)|(1<<CS00);
OCR0 = 63;
TIMSK |= (1<<OCIE0);
}
int main(void)
{
uint8_t t = 0;
DDRB = 0xFF;
timer0_init();
timer1_init();
sei();
while(1){
if (tick_1sec)
{
tick_1sec = 0;
t++;
if (t == 10){
OCR0 = 127;
}
else if (t == 20){
OCR0 = 191;
}
else if (t == 30){
OCR0 = 63;
t = 0;
}
}
}
return 0;
}
Things to check:
I recommend declaring tick_1sec as volatile to prevent the compiler of hyper-optimizing that register.
What is your clock frequency? Your ISR will deliver 1s calls only if your CPU frequency is 16MHz (==> 16.000.000 / 1024 / 15624)
You might have a LED in your hardware which you can invert from a) the ISR b) within the first if () in main to see if this is ever reached.
update: "volatile"
The link provided by #skyrift in his comment is very worth reading.
When you use Atmel Studio, compile your code once with/without the volatile keyword and compare what the compiler is doing ==> Solution explorer / Output Files / *.lss ... you will see each C statement and how the compiler converts it to machine code ... an exercise worth once in a while when working with micros ...