Ok I sought very interesting that having a keyboard in a calculator but here are my actual inventory:

Ti-84 Silver Edition
Standard PS/2 Keyboard
Cable for importing information to the calculator

Would it be possible to download the program to make the keyboard work, and would it work, if i convert it from PS/2 to the cable the calculator needs... if not what do | have to do to make this work?

You need to build what is termed a "TICI Hub" - something capable of powering the mouse and converting the calculator cable to PS/2 at the same time. My "Ultimate Calculator" had an internal TICI hub.

and how can i have that TICI HUB?....

If you want to cheat, you can just get a TI-Keyboard off ebay for around $20 for the most part. You would simply need to either splice in some wire or buy a longer I/O cord from TI directly. It will work just the same.

in other words, you are saying, it is posible to convert the PS/2 cable and make it work?...

I don't know about that, what I am saying is, Texas Instruments has keyboards for the calcs, meant for the 83+/89 line, but if you get the extra long I/O calc to calc cord, then you can use your 84+ with it as well.

Or, instead of a new cable, just write an asm program to type your text upside down.

do i have to write those programs, or can i just download them|?....

Short answer, Yes. Long answer with instructions on doing this.... <waiting for Kerm to post specifics >

As long as you build the hardware with our guidance, you can use Ben's Emerson routines:
http://benryves.com/bin/emerson/beta_2/beta_2.zip

Should be possible, it was done with a gameboy, so why not with a calculator?

It's already been done - haven't you seen my Ultimate Calc?