depthcharge
New Member
Hey i have to make a 4 bit calculator.
I have desgined most of it. i want to make a keypad(0 to 9) that will be able to give input up to 15. I have thought of one design. it would work like this :
i used 16 to 4 decimal to bcd encoder and a quad 2 bit multiplexer(74157).and a 4 bit adder.
the out put of encoder goes to data selector and adder which adds 10 to it.
if user press 0 then 4 the 4 comes out of the dataselector , if the user press 1 it changes the output of dataselector. when u again press the the digit the next output with 10 added (ie 12) goes out of the dataselector.
but i dont thing it is a good design. If any one can help me out by suggesting improvement to this design or by telling me some other design.
I have desgined most of it. i want to make a keypad(0 to 9) that will be able to give input up to 15. I have thought of one design. it would work like this :
i used 16 to 4 decimal to bcd encoder and a quad 2 bit multiplexer(74157).and a 4 bit adder.
the out put of encoder goes to data selector and adder which adds 10 to it.
if user press 0 then 4 the 4 comes out of the dataselector , if the user press 1 it changes the output of dataselector. when u again press the the digit the next output with 10 added (ie 12) goes out of the dataselector.
but i dont thing it is a good design. If any one can help me out by suggesting improvement to this design or by telling me some other design.
