Question

1. Answer all the questions given below

1. Explain the difference between edge triggered and level triggered interrupt by sketch. Where the starting address of the memory location of every interrupt is stored?

              (b) Consider the following 8051 interfacing problem. Crystal frequency: 11.059MHz. The LED  

                D8 will light up with every key press as shown below.

1. Initialize IE register for external interrupt at INT0

2. Initialize TCON register for the appropriate type of interrupt

3. Declare and define the interrupt service routine

4. Access and configure relevant pin as needed

5. Call back action in the main function as needed

Answer 1

EDGE TRIGGERING :

In a sequential circuit, if the output changes when the signal transits from a high level to a low level or from a low level to a high level, we call it edge triggering. Here, the edge that changes the voltage from low level to the high level is called rising edge (positive edge). And, the edge that changes the voltage from high level to the low level is called falling edge (negative edge).

LEVEL TRIGGERING :

In the sequential circuit, if the output changes during the high voltage period or low voltage period, it is called level triggering. In other words, the output changes during either high voltage or low voltage period- not during the edges like in edge triggering.

Difference Between Edge and Level Triggering :

Definition :

Edge triggering is a type of triggering that allows a circuit to become active at the positive edge or the negative edge of the clock signal. In contrast, level triggering is a type of triggering that allows a circuit to become active when the clock pulse is on a particular level.

Functionality :

In edge triggering, an event occurs at the rising edge or falling edge whereas, in level triggering, an event occurs during the high voltage level or low voltage level. Thus, this is the main difference between edge and level triggering.

Applications :

Furthermore, another difference between edge and level triggering is that the flip flops work according to edge triggering, whereas Latches work according to level triggering.

Conclusion :

In brief, there are two types of triggering in sequential circuits. The triggering results can change the output of the circuit. The main difference between edge and level triggering is that, in edge triggering, the output of the sequential circuit changes during the high voltage period or low voltage period while in level triggering, the output of the sequential circuit changes during transits from the high voltage to low voltage or low voltage to high voltage.

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ANSWERED AS PER MY KNOWLEDGE

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