#Arduino mega 2560 pinout interrupt software

To make sure variables shared between an ISR and the main program are updated correctly, declare them as volatile. Typically, global variables are used to pass data between an ISR and the main program. Other interrupts will be executed after the current one finishes in an order that depends on the priority they have. If your sketch uses multiple ISRs, only one can run at a time. Generally, an ISR should be as short and fast as possible. A good application of an interrupt is reading a rotary encoder or observing a user input. Interrupts are very useful in Arduino programs as it helps in solving timing problems. The only type of interrupt that the “Arduino language” supports is the attachInterrupt() function.

#Arduino mega 2560 pinout interrupt software

Software Interrupts − They occur in response to an instruction sent in software. Hardware Interrupts − They occur in response to an external event, such as an external interrupt pin going high or low.

It is possible to have that function executed automatically, each time an event happens on an input pin. At these specific conditions, the interrupt would be serviced. You can define the routine and specify conditions at the rising edge, falling edge or both. You can define a routine using a special function called as “Interrupt Service Routine” (usually known as ISR). The Arduino Mega has six hardware interrupts including the additional interrupts ('interrupt2' through 'interrupt5') on pins 21, 20, 19, and 18. Most Arduino designs have two hardware interrupts (referred to as 'interrupt0' and 'interrupt1') hard-wired to digital I/O pins 2 and 3, respectively. In this case, we are using a hardware interrupt that is triggered by a state change on one of the digital pins. Interrupts can come from various sources. Here are some important features about interrupts − When this routine finishes, the processor goes back to the main routine again. However, when an interrupt occurs the main program halts while another routine is carried out. The main program is running and performing some function in a circuit. This example explains exactly how an interrupt causes a processor to act. When the telephone conversation ends, you then go back to your main routine of chatting.

The interrupt service routine is the process of talking on the telephone. Similarly, you can think of the main routine as chatting to someone, the telephone ringing causes you to stop chatting. When you have finished your telephonic conversation, you go back to chatting with the person before the telephone rang. You stop chatting, and pick up the telephone to speak to the caller. Suppose you are sitting at home, chatting with someone. Interrupts stop the current work of Arduino such that some other work can be done.