Interrupts in Computer Systems

Interrupts are a fundamental concept in computer systems that allow the system to respond to external events or conditions in a timely manner. When an interrupt occurs, the normal execution of the program is temporarily suspended, and the system transfers control to a specific interrupt handler routine to handle the event. Interrupts are classified into different types based on their sources and priorities.

Keyboard Interrupts

In the context of keyboards, interrupt-driven input allows the system to respond immediately when a key is pressed. Instead of constantly polling the keyboard for input, which can be inefficient, the system can use interrupts to detect and handle key presses as they occur. When a key is pressed, an interrupt is generated, and the system can execute a specific interrupt handler routine to process the key press.

Interrupt Modes for Keyboard Operations

The question asks about operating a key of a keyboard in an interrupt mode. In this scenario, the system is set up to use interrupts to handle keyboard input. The specific interrupt mode used for keyboard operations is determined by the hardware and the system design.

Options Explained

The four options provided in the question are as follows:

a) ES (External Service) - This is not a commonly used interrupt mode for keyboard operations. It is primarily used for servicing hardware devices other than the keyboard.

b) EX0/EX1 - This option refers to the external interrupt sources 0 and 1. These interrupt sources are often used for keyboard operations in many microcontrollers and embedded systems. Each key press can be configured to trigger an external interrupt, allowing the system to respond to the key press in an interrupt-driven manner.

c) T0/T1 (Timer 0/Timer 1) - Timer interrupts are typically used for timing operations and may not be directly related to keyboard operations. While timers can be used in combination with interrupts to implement keyboard functionality, they are not the primary interrupt mode for keyboard operations.

d) RESET - The RESET interrupt is generated when the system is reset and is not directly related to keyboard operations.

Correct Answer: Option 'B' (EX0/EX1)

The correct answer is option 'B' (EX0/EX1) because external interrupts, specifically interrupt sources 0 and 1, are commonly used for keyboard operations in many microcontrollers and embedded systems. These interrupt sources allow the system to respond to key presses in an interrupt-driven manner, providing efficient and timely handling of keyboard input.