Whats the difference between priority and normal encoders?

[Haytham-Sief]

What is the diffrence between the priority Encoder and the normal encoder ? Plzz if any one can reply I will be thankfull. Also give me the number of an encoder without priority.
Thnx

[semiconductorman]

[size=18][b]What is the diffrence between the priority Encoder and the normal encoder ? Plzz if any one can reply I will be thankfull. Also give me the number of an encoder without priority.
Thnx

Normal encoder gives equal priority to all inputs ..while priority encoder checks gives prirority to some inputs over others ... for example..
if (cond [0] == 1)
{
q <= 1;
}
else if (cond [1] == 1)
{
q <= cond [1];
}
else
{
q <= 0 ;
}
The h/w equailvalent will be such that cond[0] if top priority ..if it is one then it does not matter if cond[1] is 0 or 1 ... the implementation is usally in a layered mux condition.

[adap]

When you want to implement a priority encoder in VHDL/Verilog you use the if-else statement. The higher the priority the lower the delay. For normal encoders you use the case statement.

[Haytham-Sief]

Thanx very much for ur help but plzzz I need more explaination , I'm not using VHDL I'm using hardware without controling I mean I cant conrol the priority of the encoder. Thnx alot

[adap]

If you are using schematics then I uploaded you two pictures of a priority and a normal encoder examples.
In priority encoder x2 has the highest priority while x0 has the lowest one.
In parallel all have the same priority.
Hope it helps

[armmips]

It is very useful. Thanks for your sharing.