Sage-Tips

How many interrupts are supported by PIC16F877A?

15
Further, there are lots of types of interrupts in Microcontroller and PIC16F877A has about 15 of them. Let us not confuse them all into our head for now.

How many interrupts are there in PIC microcontroller?

The microcontroller has 14 interrupt sources. From the diagram below you can see all the sources of the interrupts, when xxIF is an interrupt flag and xxIE is an Interrupt Enable bit.

What are the external interrupts of PIC micro controller?

PIC18F4550 has three external hardware interrupts – INT0, INT1, and INT2. They are on PORTB pins RB0, RB1, and RB2 shown in the below image. These interrupts are edge-triggered interrupts i.e. triggered by either a rising edge or by a falling edge.

What is ISR in microcontroller?

An interrupt service routine (ISR) is a software routine that hardware invokes in response to an interrupt. ISR examines an interrupt and determines how to handle it executes the handling, and then returns a logical interrupt value.

What are various types of interrupts?

Types of Interrupt

• Hardware Interrupts. An electronic signal sent from an external device or hardware to communicate with the processor indicating that it requires immediate attention.
• Software Interrupts.
• Level-triggered Interrupt.
• Edge-triggered Interrupt.
• Shared Interrupt Requests (IRQs)
• Hybrid.
• Message–Signalled.
• Doorbell.

How many interrupts are supported by PIC?

PIC 16F877A has the following 15 interrupt sources : External. Timer 0. Timer 1.

How interrupt works in a microcontroller?

When an interrupt occurs, the microcontroller runs the interrupt service routine. For every interrupt, there is a fixed location in memory that holds the address of its interrupt service routine, ISR. The table of memory locations set aside to hold the addresses of ISRs is called as the Interrupt Vector Table.

Which of the following is the common method for connecting the peripheral to the processor?

external interrupts
Explanation: The common method for connecting the peripheral to the processor is the external interrupts. The external interrupts are provided through the external pins which are connected to the peripherals.

What happens when an interrupt flag is detected during ISR?

When the interrupt flag is noticed, the “Global Interrupt Enable” bit is cleared. The appropriate ISR is run. The “Global Interrupt Enable” bit is re-set. Things now go back to step 2, unless an interrupt flag is already set during the ISR; then things go back to step 3.

How to use interrupt service routine (ISR) in a void function?

Once the RB0 pin is defined as an external interrupt pin, each time it gets low the external interrupt flag INTF will become 1 and the code inside the void interrupt function will get executed since the Interrupt Service Routine (ISR) will be called. As you can see I have named the interrupt function as ISR_example.

How to enable higher priority interrupts in a microprocessor?

However, If we have a larger system, where several devices may interrupt the microprocessor, a priority problem may arise. If you set the interrupt enable flag within the current interrupt as well, then you can allow further interrupts that are higher priority than the one being executed.

Which pin is used for external interrupt in pic16f877a?

In our case i n PIC16F877A the 33 rd pin RBO/INT is used for external interrupt. You cannot use any other pin other than this pin. The Pin connection for this circuit diagram is shown in the table below. We have enabled internal pull up resistors on PORT B, hence we can directly connect the RB0 pin to ground via a Push button.