Hi,

BCD to bin is easy.

Clear 16 bit result;
Add left digit to result;
Multiply result by 10;
Add 2nd to left digit to result;
Multiply result by 10;
Add middle digit to result;
Multiply result by 10;
Add 2nd to right digit to result;
Multiply result by 10;
Add right most digit to result;
Done!

Keyboard scanning should be explained on this site at least x times.

Happy programming.