"But brother in the HCTL datasheet there also they have shown interfacing to 8048 "

The only difference I could see is in the way the clock signal is derived for the HCTL2020. In the 8051 setup it is a dedicated one whereas in the 8048, it is from a port pin. But for that there is no problem. And I do not see why the 8051 setup + code cannot be made to work.

I have not worked with the 8748 ( fortunatley !) and cannot comment further on it.

Raghu