Huzefa Wrote:
i.e on one line 40 bits input and i need to provide these 40 bits to a driver circuit having 40 different inputs i.e one bit for each driver input
i do not need 1600 keys
the dats in in a 40*40 from not the keyboard

Then where does the subject "matrix keyboard interfacing with 8051" fits in??

Did not you read "Use descriptive subject" when you started the post?