Question

Which of the following is mode 0 in 8253?

(a) interrupt on start count

(b) interrupt for wait statement

(c) interrupt on terminal count

(d) no interrupt

I have been asked this question in examination.

I need to ask this question from Timer in section Basic Peripherals of Embedded Systems

Answer 1

The correct option is (c) interrupt on terminal count

Explanation: The interrupt on the terminal count is known as mode 0 for the 8253.  An initial value is loaded into the count register and then starts to count down at the frequency which is determined by the clock input. When the count reaches zero, an interrupt is generated.