Mehdi,

where do you have these two from?
http://www.8052.com/users/MEHDI/ques2.JPG - 5. programming model
http://www.8052.com/users/MEHDI/ques3.JPG - 6.2. BIU programming

I think you messed up the HOST interface with the INTERNAL DSP specification.

As far as I understand, there are NO registers, only 16-bit commands. So the procedure I think roughly is:
- write LOW byte of 16-bit command
- write HIGH byte of 16-bit command
- wait for ACK (see page 33 for how long you need to wait)
- read LOW byte of 16-bit status
- read HIGH byte of 16-bit status

I would consider connecting the HI/LO pin to some address pin so you can do movx to two different addresses for faster access (if faster access needed at all...).

Jan Waclawek