|Briefly explain any 4 modes of operation of the 8254 interval timer.
06-12-2012 02:32 AM
Briefly explain any 4 modes of operation of the 8254 interval timer.
The following are the modes of operation of the programmable timer 8254:
- Mode 0: Also known as the interrupt on terminal count. In this mode the output is initially low. Once the count of terminal is reached the output becomes high.
- Mode 1: Programmable one shot is also known as the hardware triggered one-shot. For it to happen, the count registers must be loaded and the A 0-1 pulse has to be sent to the Gate input in order to trigger the counter.
- Mode 2: Rate generator, this process is repeated indefinitely.
- Mode 3: Square wave generator, when gate=1, The out is a square wave where the high pulse is equal to the low pulse of N is an even number. In case the N is an odd number the high pulse is longer. The mode-3 is commonly used for as frequency divider.