Call value from KeyPressFcn GUI to another function m file

Hi everyone, I have 1 GUI that user put value on edittext, and other .m file must call it for do some calculation. how can I do that? need your advice, many thanks.

for example : here is code from GUI #1 (Form_Embedd)

 function edt_katakunci_KeyPressFcn(hObject, eventdata, handles)
 %this is function when user type password on edittext box
 pass = get(handles.edt_katakunci,'UserData');
 set(handles.edt_katakunci,'UserData',pass)

and I need call the value to another m file for convert value as hex and hex value calculate on m file (convert.m).

on .m file (convert.m) value from form_main edt_katakunci called and stored into this code

   Form_Embedd(edt_katakunci_KeyPressFcn(pass))
   kata=pass;
   kunci=sprintf('%X', kata);

but when I run this code the result is

??? Undefined function or variable 'pass'.*

[Shivaputra Narke]

what is the aim of following code?

 pass = get(handles.edt_katakunci,'UserData');
 set(handles.edt_katakunci,'UserData',pass)
?
Can you explain in detail?