How to read a key in graph mode

[mobilef]

I made a welcome screen by graph mode. When user wants to start then program, he/she needs to press a key.
But how to read a key in graph mode?

I used:
...
...
ch := readkey;
if readkey <> #0 then
closegraph
...
...
But it isn't work. The key is read in the main program, not the graph mode screen.

How to do that?
Thanks.

 

[Glenn9999]

use the CRT unit.

 

[mobilef]

yes, i used crt unit, but also not work.
thanks.