In avr Xmega device, there are only two IO port interrupt vectors INT0 and INT1.
I have three switches that should generate three interrupts.
I have written an interrupt code for the first switch using INT0. Now, I can write the second interrupt using INT1 which will exhaust my vectors.
Below is my code for INT0 ISR:
ISR (PORTD_INT0_vect){
PORTD.INTFLAGS = 0x01; // clear INT0IF flag.
PORTD_OUT = PORTD_OUT | (1<<4); // led on.
}
Can I redefine this ISR to enable interrupt for second switch?
The registers that I set in main function are as follows:
PORTD.INT0MASK = 0x04; // PD2 is the source of interrupt for INT0.
PORTD.INTCTRL = 0x03; // Disable INT1, enable INT0 and place it a high-priority level.
PORTD.PIN2CTRL = 0x03; // configure PD2 pin to interrupt on the low level of signal.
PMIC.CTRL = 0x07; // enable high,medium, and low level interrupts.
sei(); // enable interrupt globally.
The idea of the external interrupts is that you get to know that something happened, but not what happened. In your ISR you have to read out the state of the inputs the switches are connected to and determine based on the readout, what to do. To detect, if the state did alter, keep a copy of the ports input status and do an XOR with the newly read out value (do this for a whole port, not just for single pins).
I'm not expert of XMEGA, but I can suggest, for example using PD1 as interrupt pin:
PORTD.INT0MASK = 0x04; // PD2 is the source of interrupt for INT0.
PORTD.INT1MASK = 0x02; // PD1 is the source of interrupt for INT1.
PORTD.INTCTRL = 0x0F; // Enable INT1, enable INT0 and place them a high-priority level.
PORTD.PIN2CTRL = 0x03; // configure PD2 pin to interrupt on the low level of signal.PORTD.PIN1CTRL = 0x03; // configure PD1 pin to interrupt on the low level of signal.
Every port has 2 interrupts. You can use more ports if you need more interrupts than 2. You can connect the third switch to a second port and use the INT0 there.
How about polling input(s) from your code, in a loop or from timer interrupt routine(s)? This way you can handle as many input signals as you have inputs capable of sensing the signal change.
The limiting factor, though is the frequency of polling and the delay the polling software introduces.
Of course I assume you want to observe high/low levels of the signal. For more elaborate signal sensing (rising, fallsing, frequency change) the use of ADC is unavoidable.
I hope this helped.
Related
Summary:
An ISR necessarily causes its own trigger pin to toggle randomly multiple times. These toggles (during the ISR) should be ignored, but aren't, and result in another interrupt to be set as pending and get executed afterwards.
I have a serial bit-bang device that I read via an interrupt. Device has a data pin and a "clock" pin. Data pin is HIGH by default. When the device is ready to be read, it pulls this data pin LOW. After this falling edge, each pulse on the "clock" pin shifts one bit out to the data pin.
An interrupt triggers on the falling edge of the data pin, and ISR bangs 24 bits of data out of the same data pin. Therefore, additional random falling edges on the data pin causes another interrupt to be set as pending. Which triggers immediately after the actual ISR has returned, resulting two consecutive interrupts being run per one "real" interrupt.
I have tried multiple ways to disable interrupts and/or clear pending interrupts, none of which seem to have any effect whatsoever. I suspect that this is because manipulating interrupt related registers is not allowed/or ignored in an ISR.
The device is Atmel ATSAMD21. (ARM Cortex M0+). Code is built under Atmel Studio with optimisation level -Og.I am okay with using ASF and/or SAM libraries/definitions, ARM CMSIS or baremetal register manipulation. Whichever happens to work.
Here is what I tried so far:
void interrupt_cb ( void )
{
// Trying to disable interrupts
// Executed at the beginning of the ISR
NVIC_DisableIRQ(EIC_IRQn);
ext_irq_disable( <pin> );
__disable_irq();
// body
// < code that results in same pin >
// < that the interrupt is triggered >
// < to be toggled randomly. >
// Trying to clear pending interrupts
// Executed just before the ISR returns.
NVIC_ClearPendingIRQ( EIC_IRQn );
NVIC->ICPR[0] |= 4; //probably same as the above
EIC->INTENCLR.bit.EXTINT2 = 1;
}
Or a combination of these commands.
void EXTI4_15_IRQHandler()
{
if(EXTI->PR & EXTI_PR_PR8)
{
EXTI->PR |= EXTI_PR_PR8;
// handle interrupt here
GPIOA->BSRR |= GPIO_BSRR_BS_10;
Delay(500);
GPIOA->BSRR |= GPIO_BSRR_BR_10;
Delay(500);
}
}
the interrupt init is initialized in the main.c and the setup is correct.
Is there anything that i am missing in the handler function?
You have posted only interrupt handler function, which is not a big help on its own. Basically, your MCU either enters it and executes it entirely or not. So if it (the interrupt handler) doesn't run, it means, the interrupt is not triggered. It means, the problem is somewhere else, so I will go over the entire logic of getting EXTI interrupt on STM32, make sure you have all of that done.
In order to get EXTI interrupts working, we need to connect 3 internal peripherals together: GPIO, EXTI and NVIC. You haven't indicated a specific microcontroller, but they all (STM32) do it in the same/similar way, so I will use STM32F746 as an example, since I have it here on my table.
First, you need to set up EXTI. If you want an interrupt on pin GPIOx8, you need to set bits 8 in the appropriate places in the EXTI registers depending on the event you want to trigger an interrupt.
Second of all, you need to connect GPIO port to EXTI. Do you want an interrupt on PA8? Or PB8? Or PC8? EXTI only understands that it's "Pin 8". It doesn't know if it's PA8 or PB8. That you do in SYSCFG peripheral. In the register EXTI->EXTICR3 you need to set port for EXTI8. This is where you decide that it's PB8 and not PA8 that triggers the interrupt, or whatever port you have.
Now, upon the GPIO behavior event defined in EXTI, the EXTI will report an EXTI9_5 event to NVIC. For now, NVIC will set pending bit if EXTI interrupt event occurs, but it will not execute the interrupt, because it's not activated. So we need to configure NVIC and activate EXTI9_5 interrupt there. At this point your interrupt should work.
To recap, the sequence of actions is the following:
Configure EXTI with the number of pin, on which you want interrupt. Number of pin, but not a GPIO port. For you, it will be pin 8.
Configure SYSCFG to select GPIO port for that EXTI pin. Configure pin 8 to be pin PB8 and not PA8 (or whatever port the interrupt is on).
Activate the corresponding NVIC interrupt.
From this also follows, that you can't have interrupts on PA8 and PB8 at the same time.
EDIT: having delays in the ISR is highly inadvisable. Also, make sure your input signal on the interrupt pin is debounced.
EDIT2: I assumed it goes without saying that every peripheral you use requires clock to be supplied to it.
I am trying to make it so that then PINB7 is pressed (which is pin of botton) LED to light up.
PINB7 is PCINT8 on board.
So i set
PCICR|=(1<<1);//enable interrupts for pins 14-8
sei();
PCMSK1|=(<<PCINT8); // mask for pin 8
i don't get what vector i should use in ISR. From what i saw I should just do PCINT8_vect, however vector doesn't get highlighted like then i use "TIMER2_COMPB_vect".So does PCINT8 vector not exist or is there way to use PCINT0 and 1 for this?
Apparently , on mega328pb , there is no vectors for individual pin interrupts but there are vectors for PCIE0,1,2,3.
0- bits 0:7
1-8:14
2-16:23
3-24:27
so if u want to use interrupt for pin b7.
PB7 is PCINT7(can be seen in chapter about i/o ports).
So id have to enable PCIE0 in PCIRC register, correct mask it TMSK0. and use ISR(PCINT0_vect).
But if you have interrupt on PCINT6 and PCINT7 , you need if else in ISR to determine which of 2 pins triggered interrupt
I'm using an Arduino Uno with the Atmega328p microcontroller. I'm trying to use INT1 as a software interrupt. I manually set INT1's associated PORTD3 high or low depending on external info. What I want is to set the pin high or low at the startup of the device and then enable the interrupt on the pin without causing an interrupt if i set the pin high before enabling the interrupt.
It doesnt seem to matter where I enabled the interrupt--if i changed the state of the pin at some point the interrupt will occur once its enabled. Here is a snippet of the code:
int main(void)
{
DDRD |= (1<<DDD7)|(1<<DDD3);//7 for siren 3 for software int1
USART_Init(MYUBRR);//Initialize USART
while(door!='C' && door!='O'){//get door state on startup
door = getDoorState();
}
if(door=='O')
PORTD |= 1<<PORTD3;
else
PORTD &= ~(1<<PORTD3);
EIFR &= ~(1<<INTF1);//clear flag bit before enable, I'd heard this may help????
EIMSK |= (1<<INT1);//enable door switch interrupt
EICRA |= (1<<ISC00)|(1<<ISC10);//int1 and int0 set for any logical change
sei();//global interrupt enable
while (1)
{}
}
As soon as the global interrupt is enabled by a call to sei() the interrupt will occur if PORTD3 is high, regardless of where PORTD3 was set high or where sei() is. Calling sei() should never cause an interrupt in this code, ideally.
4386427 is correct. The bit is cleared by setting it to a one, not zero. Seems counter-intuitive to me so it threw me off but it works now.
EIFR |= (1<<INTF1);
EIFR &= ~(1<<INTF1) is incorrect.
The correct way of doing this is EIFR = 1<<INTF1.
Datasheet says: the flag is cleared by writing a '1' to it.
i am trying to setup an UART interrupt to trigger when a character is entered on the UART screen. The thing is the way i have set it up it seems that the interrupt triggers when transmitting and receiving. I have read the data sheet and it doesnt really say if it can be done and how. Its just says that a interrupt for serial port is avaiable.
This is how i have set up the uart
S0CON = 0x50;
PCON |= 0x80; /* Double Baud rate */
ADCON0 |= 0x80; /* Use baudrate generator */
S0RELL = 0xCC; /* Baudrate = 9614 Baud # 16Mhz */
S0RELH = 0x03;
TI0 = 1; /* Ready to transmit */
ES0 =1;
Does anyone possibly have any idea how this can be accomplished??
I am using Keil compiler and the Infineon C509
Datasheet **link fixed
Thank you
Unfortunately, it doesn't look like you'll be able to do what you want cleanly. Taking a look at the user manual--the data sheet is typically insufficient for this type of problem--check out Figure 7.4. The send and receive interrupt flags set by hardware for channel 0, TI0 and RI0, both trigger the default serial communication interrupt, and it doesn't appear that either can be disabled.
There might be other options, but I'd consider one of the following:
Polling (vs. using any interrupts for the UART)
Use the interrupt as you have it working, but check first thing in your serial comms interrupt that RI0 is set and if it's not, exit immediately. (Just make sure there's not any kind of timing problem with respect to this and clearing the receive flag to make sure you don't have any potential for dropping a byte.)
Link to C509-L user manual (not sure how long it'll persist): Infineon product site