4 Bit Priority Encoder Circuit Diagram. The logic diagram of 4 input priority encoder is implemented by corresponding output expressions obtained from k map simplification. For example if i7 i6 and i0 bits of an 8 bit input are high then the output 111 will be for i7.
4 to 2 priority encoder. Inputs containing 2 3 or 4 high bits the lower priority bits are shown as don t cares x. A priority is assigned to each input so that when two or more inputs are simultaneously active the input with the highest priority is represented on the output with input line a8 having the highest priority.
Let s write the truth table for a 4 2.
A1 a0 here the input y3 has the highest priority whereas the input y0 has the lowest priority in this case even if more than one input is 1 at the same time the output will be the binary code corresponding to the input which is having higher priority. A1 a0 here the input y3 has the highest priority whereas the input y0 has the lowest priority in this case even if more than one input is 1 at the same time the output will be the binary code corresponding to the input which is having higher priority. The block diagram of a 4 2 priority encoder is shown below a priority 4 2 encoder also has 4 inputs and 2 outputs but we will add another output called v which stands for valid bit. In the truth table for all the non explicitly defined input combinations the input containing 2 3 and 4 high bits the lower priority bits are shown as don t care.
