I am using an arduino leonardo (ATmega32u4) to check if the value of a (analog) pressure sensor is above a certain threshold. I am using timer4 of the ATmega32u4 and mad a overflow timer as well as an output compare timer. The functionality and efficiency of both timers seem to be the same but I suppose one of them should be better. Does anyone know which one should be more efficient in this case?
Below the timer functions.
void setupOvfTimer4() {
//clear timer4 registers
OCR4C = 0;
TCCR4A = 0;
TCCR4B = 0;
TCCR4C = 0;
TCCR4D = 0;
TCCR4E = 0;
TCNT4 = 0; //clear timer4 count register
TIMSK4 |= (1<<TOIE4);
TCCR4B |= (1 << CS42 ) | (1<<CS41) | (1<<CS40); //sets prescaler to 64
OCR4C = 249; //with prescaler /64 and 16 MHz clock this triggers every ms. (this is TOP).
}
void setupOcrTimer4() {
TCCR4A = 0; //Clear timer 4 register A
TCCR4B = 0; //Clear timer 4 register B
TCNT4 = 0; //Clear timer 4 counter register
OCR4A = 249; //Set timer 4 output register A to timer4Frequency (Hz)
TCCR4B |= (1 << CS41); //Set timer 4 to compare mode (CTC)
TCCR4B |= (1 << CS40);
TCCR4B |= (1 << CS42); //Set no prescaler (16E6MHz / 1000Hz = 16e3 < 65535)
TIMSK4 |= (1 << OCIE4A); //Enable ISR immediately
}
Related
I'm trying to run two functions 'similtaniously' via interrupts:
1) Measure ADC via timing of timer 0 (100Hz) and show results on pin 0-5
2) Blink a led via timer 1 (10Hz) on pin 6.
Problem seems to be that the ISR of timer 1 blocks the function, so nothing else is executed. Here is the code:
(Please don't be offended by any styling mistakes, the code is under development)
#define F_CPU 16000000UL // 16MHz Clock speed
#include <avr/io.h>
#include <avr/interrupt.h>
void ADC_init(void);
void SetTimer0(void);
void SetTimer1(void);
int main(void)
{
DDRB |= (1<<DDB0) + (1<<DDB1) + (1<<DDB2) + (1<<DDB3) + (1<<DDB4) + (1<<DDB5) + (1<<DDB6);
PORTB = 0b00000000;
DDRB &= ~(1<<DDB7);
ADC_init();
SetTimer0();
SetTimer1();
while(1){
}
}
void ADC_init(void)
{
cli();
// Select Vref=AVcc
// and set left adjust result
// select pin ADC0 (PC0)
ADMUX |= (1<<REFS0)|(1<<ADLAR);
//and enable ADC
//enable ADC interupt
//enable autotriggering
//set prescaller to 128
ADCSRA |= (1<<ADEN) | (1<<ADATE) | (1<<ADIE) | (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0);
//set ADC trigger source - Timer0 compare match A
ADCSRB |= (1<<ADTS1)|(1<<ADTS0);
// StartADC
ADCSRA |= (1<<ADSC);
sei();
}
//initialize timer0 match A on 100hz
void SetTimer0(void)
{
cli();
TCCR0A = 0; // set entire TCCR0A register to 0
TCCR0B = 0; // same for TCCR0B
TCNT0 = 0; // initialize counter value to 0
// set compare match register for 100Hz increments
OCR0A = 155; // = 16000000 / (1024 * 100.16025641025641)-1
// toggle PD6/OC0A pin on compare match
TCCR0A |=(1<<COM0A0)|(1<<WGM01);
//Set CTC mode
TCCR0B |= (1 << WGM01);
// Set CS02, CS01 and CS00 bits for 1024 prescaler
TCCR0B |= (1 << CS02) | (0 << CS01) | (1 << CS00);
// enable timer compare interrupt
TIMSK0 |= (1 << OCIE0A);
sei();
}
//initialize timer1 10hz
void SetTimer1(void){
cli();
TCCR1A = 0; // set entire TCCR1A register to 0
TCCR1B = 0; // same for TCCR1B
TCNT1 = 0; // initialize counter value to 0
// set compare match register for 10 Hz increments
OCR1A = 24999; // = 16000000 / (64 * 10) - 1 (must be <65536)
// turn on CTC mode
TCCR1B |= (1 << WGM12);
// Set CS12, CS11 and CS10 bits for 64 prescaler
TCCR1B |= (0 << CS12) | (1 << CS11) | (1 << CS10);
// enable timer compare interrupt
TIMSK1 |= (1 << OCIE1A);
sei();
}
// ADC done interrupt
ISR(ADC_vect)
{
// Clear timer compare match flag
TIFR0=(1<<OCF0A);
// save ADC measurement
uint16_t val = ADC;
// show ADC results
if (val < 100)
{ PORTB = 0b00000000; }
else if (val < 300)
{ PORTB = 0b00000001; }
else if (val < 550)
{ PORTB = 0b00000011; }
else if (val < 850)
{ PORTB = 0b00000111; }
else if (val < 1020)
{ PORTB = 0b00001111; }
else
{ PORTB = 0b00011111; }
}
ISR(TIMER1_COMPA_vect)
{
//PORTB ^= PINB5;
static uint16_t on = 0;
if (on == 1){
PORTB = 0b00100000;
on = 0;
}
else {
PORTB = 0b00000000;
on = 1;
}
}
When the SetTimer1() function is disabled the DCA runs as expected. So individually are are both ISR's working fine, but together not. Could someone help me solve this problem?
You have output compare interrupt enabled fro Timer0:
// enable timer compare interrupt
TIMSK0 |= (1 << OCIE0A);
but no ISR handler for that interrupt.
The default __bad_interrupt handler just performs jump to zero interrupt vector, i.e. restarts the program.
That means if you have an interrupt enabled there should be an ISR for that interrupt.
I want to transfer data from an external AD-Converter. I get parallel 11 bits which I store in an array. I wanna set up a timer triggered GPDMA transfer, that every 50ns fires a DMA stream and transfer data. After the transfer is complete, the RAM address should be incremented.
The MCU, I work with is the LPC4088 Quickstart Board.
The CPU and Peripheral Clock, runs with 120Mhz
I studied the UM of LPC4088 and already wrote some simple basic code.
#include "LPC407x_8x_177x_8x.h"
#define PERIPHSRAM1 0x20004000
char adcData[11] = {1,1,1,1,1,1,1,1,1,1,1};
volatile uint32_t DMATCCOUNT = 0;
volatile uint32_t DMAERRCOUNT = 0;
int main(){
uint8_t size = sizeof(adcData);
LPC_SC->PCONP |= (1 << 22); //Power & Clock Timer2
LPC_TIM2->CTCR = (0 << 0); //Timer Mode
LPC_TIM2->PR = 0;
LPC_TIM2->TCR = (1 << 1); //Reset timer
LPC_TIM2->TC = 0;
LPC_TIM2->MR0 = 5; //Match register to get 10MHz
LPC_TIM2->MCR = (1 << 1) //Reset Timer
|(1 << 0); //Interrupt if MR0 matches
LPC_TIM2->EMR = 0x31; //toggle pin to check wave output
LPC_TIM2->TCR = (1 << 1); //reset timer again
LPC_SC->PCONP |= (1 << 29); //Power & Clock DMA
LPC_GPDMACH0->CConfig = 0; //disable CH0
LPC_GPDMA->Config |= (1 << 0); //enable DMA Controller
LPC_SC->DMAREQSEL = 0x010; //Set T2 MAT0 as DMA request
LPC_GPDMA->IntErrClr |= 0x0FF;
LPC_GPDMA->IntTCClear |= 0x0FF;
LPC_GPDMACH0->CDestAddr = PERIPHSRAM1;
LPC_GPDMACH0->CSrcAddr = (uint32_t) &adcData;
LPC_GPDMACH0->CControl = size
|(0x00 << 12) //Source Burst size: 1
|(0x00 << 15) //Destination Burst size: 1
|(0x02 << 18) //Source width: 32 bit
|(0x02 << 21) //Destination width:32 bit
|(0x01 << 26) //Source increment: enabled
|(0x01 << 27) //Destination increment: enabled
|(0x01 << 31); //TermCount interrupt enabled
LPC_GPDMACH0->CControl |= (4 << 1) //Source peripheral: Timer2 MR0
|(0 << 11); //Memory to memory trasnfer
NVIC_SetVector(DMA_IRQn, (uint32_t) DMA_IRQHandler);
NVIC_EnableIRQ(DMA_IRQn);
LPC_GPDMACH0->CConfig |= 1; //Enable channel
LPC_TIM2->IR |= 0x0FF; //CLear all timer interrupts
LPC_TIM2->TCR = 0x01; //start Timer
while(!DMATCCOUNT); //Wait till transfer Complete
while(1){
}
}
void DMA_IRQHandler(void){
uint32_t temp;
DMATCCOUNT++;
temp = LPC_GPDMA->IntTCStat;
if(temp){
DMATCCOUNT++;
LPC_GPDMA->IntTCClear |= temp;
}
temp = LPC_GPDMA->IntErrStat;
if(temp){
DMAERRCOUNT++;
LPC_GPDMA->IntErrClr |= temp;
}
return;
}
I expected data on address 0x20004000, but there is nothing.
Hope any of you guys could help me.
I am using an Atmega328p-pu. I am trying to use the timer 1 for both a 16 bit PWM as well as using the overflow inturrupt to increment a timer. My code is below, I also set the F_CPU to 8000000UL in the make file.
I would like the to have a variable that counts up for a defined amount of time and then resets and continues. so far I would expect it to count up for 7.5 seconds. I believe I should have a clock frequency of 8 MHz, then with fast PWM with a 1 prescaler and ICR1 at 5000 I would expect the inturrupt to happen at 1600 Hz. Then I let it count up for 12000 counts. I would expect this to take 7.5 seconds. but I've measured it at around 57 seconds. I'm not sure what I'm missing, maybe something in the setting of the registers, but I'm not sure where. thanks for your help,
here is what I think is most important,
// values for timer1
// WGM 13 12 11 10 is
// fast PWM 1 1 1 0
TCCR1A |= (1 << 7); // output on A pin (COM1A1)
TCCR1A |= (1 << 1); // WGM 11
TCCR1A &= ~(1 << 0); // WGM 10
TCCR1B |= (1 << 4); // WGM 13
TCCR1B |= (1 << 3); // WGM 12
//for prescaler of 1 set CS12 CS11 CS10
0 0 1
TCCR1B &= ~(1 << 2); // set prescaler to 1x CS12
TCCR1B &= ~(1 << 1); // set prescaler to 1x CS11
TCCR1B |= (1 << 0); // set prescaler to 1x CS10
TIMSK1 = 0; // enable output compare A inturrupt
TIMSK1 |= (1 << 0); // Set the Overflow inturrupt
TCNT1 = 0; // set the counter to zero on startup
ICR1 = 5000; //Set the top of the counter
OCR1A = 0; //set the duty cycle
....
ISR(TIMER1_OVF_vect){
longTimer++;
....
if (longTimer >= 12000){
longTimer = 0;
and here is the entire code
/* Light Control */
// ------- Preamble -------- //
#include <avr/io.h> /* Defines pins, ports, etc */
#include <avr/interrupt.h>
// Global variables
volatile uint8_t tick = 0;
volatile uint8_t fastTimer = 0;
volatile uint16_t longTimer = 0;
volatile uint16_t fader = 0;
volatile uint16_t dayBrightness = 0;
volatile uint8_t nightBrightness = 0;
uint8_t Day = 0;
void init(void) {
// values for push button inturrupt
EIMSK = (1 << 0);
EICRA = (1 << 1) & (1 << 0);
// values for timer1
// WGM 13 12 11 10 is
// fast PWM 1 1 1 0
TCCR1A |= (1 << 7); // output on A pin (COM1A1)
TCCR1A |= (1 << 1); // WGM 11
TCCR1A &= ~(1 << 0); // WGM 10
TCCR1B |= (1 << 4); // WGM 13
TCCR1B |= (1 << 3); // WGM 12
//for prescaler of 1 set CS12 CS11 CS10
0 0 1
TCCR1B &= ~(1 << 2); // set prescaler to 1x CS12
TCCR1B &= ~(1 << 1); // set prescaler to 1x CS11
TCCR1B |= (1 << 0); // set prescaler to 1x CS10
TIMSK1 = 0; // enable output compare A inturrupt
TIMSK1 |= (1 << 0); // Set the Overflow inturrupt
TCNT1 = 0; // set the counter to zero on startup
ICR1 = 5000; //Set the top of the counter
OCR1A = 0; //set the duty cycle
sei();
// values for IO
DDRB |= 0b00000011; /* Data Direction Register B: writing a one to the bit enables output. */
DDRD = 0x00; /* zero sets all as input */
PORTD = 0xff; /* set all inputs as pull ups */
}
ISR(INT0_vect){
//longTimer = 0;
}
ISR(TIMER1_OVF_vect){
longTimer++;
if(Day){
fader++;
}
else{
if(fader > 0){
fader--;
}
}
}
int main(void) {
init();
// ------ Event loop ------ //
while (1) {
if(Day) {
if (fader >= 5000){
OCR1A = 5000;
}
else {
OCR1A = fader;
}
}
else {
OCR1A = fader;
}
if (longTimer >= 12000){
longTimer = 0;
if(Day){
fader = 5000;
}
else{
fader = 0;
}
tick = 1;
}
if (tick == 1){
Day ^= 1;
tick = 0;
}
} /* End event loop */
return 0; /* This line is never reached */
}
Whenever I'm using the internal oscillator and things are running either way (8x) faster, or way (8x) slower, I check the CKDIV8 bit setting. Almost always that's the culprit.
If using an external oscillator or clock, weird timings are often from not switching the the external clock in the fuse settings, or from having F_CPU set differently from actual frequency.
Also, off-topic a bit, but code such as this is redundant:
TCCR1B &= ~(1 << 2); // set prescaler to 1x CS12
TCCR1B &= ~(1 << 1); // set prescaler to 1x CS11
Those bits are zeroes by default so no reason to clear them unless it's just for clarity as you're learning.
I am using AVR Studio5 to program the arduino uno rev3 with atmel atmega328p.Now , I am trying blink a led continuously within 1 second .
The code is :
PORTD = 0b10001010;
TCNT1H = 0xBB;
TCNT1L = 0xBB;
TCCR1A = 0;
TCCR1B = 5; // prescaler is 1024
while((TIFR1 & (1<<TOV1)) == 0)
{
temp = TCNT1H;
while ((TCNT1H - temp) >= 11);
PORTD ^= 1<<7; // blinking as expected
}
TIFR1 = 1<<TOV1;
TCCR1A = 0;
TCCR1B = 0;
The above code shows that I use a timer1 lasting for 1 second in which I attempt to blink the PORTD.7 led for each 0.032768s.
But , now , the problem is that the timer works for delaying 1 second but the led keep lighting without blinking . Please help .
( P.S the circuit works fine )
Complement :
If I use the following code , it shows the led blinking.
for ( a = 0;a<2;a++)
{
PORTD = 0b00001010;
TCNT1H = 0xEE;
TCNT1L = 0xEE;
TCCR1A = 0;
TCCR1B = 5; // prescaler is 1024
while((TIFR1 & (1<<TOV1)) == 0);
TIFR1 = 1<<TOV1;
TCCR1A = 0;
TCCR1B = 0;
PORTD = 0b10001010;
TCNT1H = 0xEE;
TCNT1L = 0xEE;
TCCR1A = 0;
TCCR1B = 5; // prescaler is 1024
while((TIFR1 & (1<<TOV1)) == 0);
TIFR1 = 1<<TOV1;
TCCR1A = 0;
TCCR1B = 0;
}
But , for the simplicity , I prefer the most top method if working .
while ((TCNT1H - temp) >= 10)
{
PORTD ^= 1<<7; // blinking as expected
}
You are blinking too fast, so fast that actually what are you are seeing is a LED with half the luminosity. You need to add some delay between two invocations of PORTD ^= 1<<7.
This is something that should be done with an interrupt.
void TMR_init(void)
{
DDRD|=_BV(PD7); //bit 7 of port D to output
TCNT1=0; //reset the timer counter
OCR1AL=0xC6; //depends on your osc. This values are for 12MHz
OCR1AH=0x2D; //with 12 000 000Hz / 1024 it takes 11718 ticks for 1 sec->0x2D C6
TIMSK1|=_BV(OCIE1A); //enable interrupt on output compare A (when timer value == value in the OCR1AL/H-registers)
TCCR1A=0; //normal operation
TCCR1B=_BV(CS12) | _BV(CS10); //prescaler 1024 and starts the timer
sei(); //enable interrupts
}
//isr
SIGNAL(TIMER1_COMPA_vect)
{
PORTD^=_BV(PD7); //toggle
}
This code should work but is untested. Don't forget to include avr/interrupt.h. Some macros may differ due to version differences of the compiler.
I am calibrating the AVR Butterfly internal oscillator for being able to use USART, based on the sample code provided by AVR (see code below). As I also wanted to use two timer-controlled servo motors, I am wondering whether it is possible to reuse 16-bit timer 1 after the calibration process - I tried resetting the TCCR1A/B but it did not work out (code also below). I hope you can help me out with this.
void OSCCAL_Calibrate(void){
unsigned char calibrate = 0;
int temp;
unsigned char tempL;
CLKPR = (1<<CLKPCE); // set Clock Prescaler Change Enable
// set prescaler = 8, Inter RC 8Mhz / 8 = 1Mhz
CLKPR = (1<<CLKPS1) | (1<<CLKPS0);
TIMSK2 = 0; //disable OCIE2A and TOIE2
ASSR = (1<<AS2); //select asynchronous operation of timer2 (32,768kHz)
OCR2A = 200; // set timer2 compare value
TIMSK0 = 0; // delete any interrupt sources
TCCR1B = (1<<CS10); // start timer1 with no prescaling
TCCR2A = (1<<CS20); // start timer2 with no prescaling
while((ASSR & 0x01) | (ASSR & 0x04)); //wait for TCN2UB and TCR2UB to be cleared
delayMs(1000); // wait for external crystal to stabilise
while(!calibrate)
{
cli(); // disable global interrupt
TIFR1 = 0xFF; // delete TIFR1 flags
TIFR2 = 0xFF; // delete TIFR2 flags
TCNT1H = 0; // clear timer1 counter
TCNT1L = 0;
TCNT2 = 0; // clear timer2 counter
while ( !(TIFR2 & (1<<OCF2A)) ); // wait for timer2 compareflag
TCCR1B = 0; // stop timer1
sei(); // enable global interrupt
if ( (TIFR1 & (1<<TOV1)) )
{
temp = 0xFFFF; // if timer1 overflows, set the temp to 0xFFFF
}else
{ // read out the timer1 counter value
tempL = TCNT1L;
temp = TCNT1H;
temp = (temp << 8);
temp += tempL;
}
if (temp > 6250)
OSCCAL--; // the internRC oscillator runs to fast, decrease the OSCCAL
else if (temp < 6120)
OSCCAL++; // the internRC oscillator runs to slow, increase the OSCCAL
else
calibrate = 1; // the interRC is correct
TCCR1B = (1<<CS10); // start timer1
}
}
void motorInit(){
// reset timer 1
TCCR1A = 0;
TCCR1B = 0;
// initialize Servo Pins
DDRB |= (1<<PB5) | (1<<PB6);
ICR1H = ICR_VALUE >> 8;
ICR1L = ICR_VALUE & (TOP_VALUE);
// reset OCRs
setServoSpeed(0, 0);
setServoSpeed(1, 0);
// Set Timer mode (PWM Phase & Freq. correct, clear on compare match)
// and prescaler (8)
TCCR1A = ((1<<COM1A1) | (1<<COM1B1));
TCCR1B = ((1<<WGM13) | (0<<CS12) | (1<<CS11) | (0<<CS10));
}
Maybe you can check code which I used for a project while ago, but you should take care that I decreased the system frequency to 7.3768 MHz for 56700 baudrate, which maybe you need to adjust.
void OSCCAL_Calibrate(void)
{
uint8_t LoopCount = (0x7F / 2);
ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
{
// Make sure all clock division is turned off (8MHz RC clock)
CLKPR = (1 << CLKPCE);
CLKPR = 0x00;
// Inital OSCCAL of half its maximum
OSCCAL = (0x7F / 2);
// Disable timer interrupts
TIMSK1 = 0;
TIMSK2 = 0;
// Set timer 2 to asyncronous mode (32.768KHz crystal)
ASSR = (1 << AS2);
// Ensure timer 1 control register A is cleared
TCCR1A = 0;
// Start both counters with no prescaling
TCCR1B = (1 << CS10);
TCCR2A = (1 << CS20);
// Wait until timer 2's external 32.768KHz crystal is stable
while (ASSR & ((1 << TCN2UB) | (1 << TCR2UB) | (1 << OCR2UB)));
// Clear the timer values
TCNT1 = 0;
TCNT2 = 0;
while (LoopCount--)
{
// Wait until timer 2 overflows
while (!(TIFR2 & (1 << TOV2)));
// Stop timer 1 so it can be read
TCCR1B = 0x00;
// Check timer value against ideal constant
if (TCNT1 > OSCCAL_TARGETCOUNT) // Clock is running too fast
OSCCAL--;
else if (TCNT1 < OSCCAL_TARGETCOUNT) // Clock is running too slow
OSCCAL++;
// Clear timer 2 overflow flag
TIFR2 |= (1 << TOV2);
Check this out!