Parallel interfacing between AT89c51 and AT89c52

I am trying to control the activity of 89c51 which is used as a slave using 89c52 which is used as master. Initially, data has been sent from 89c51 to 89c52 through the data port (P3 for 89c51 and P1 for 89c52)without any problem. But after that data transmission in reverse direction is not possible. I have tried it in many alternative ways,like I have tried the data transmission from 89c52 to 51 through a different port(P3 of 89c52) receiving port of 89c51 as P1. In this case I see data is written to the port but not recieved in the variable of 89c51. My question is what is the reason behind this? Am I missing something or parallel communication is not possible in this fashion? I am using Keil and Proteus. I am also attaching the files. As 89c51 is at left in the circuit,the hex file is renamed as mc_left and for 89c52 the hex file is renamed as mc_right.

Dear friend,
for your kind information in parallel communication you can transmit data in any direction from slave or master. so,that here i suggest that 1st check the code and it will be better if you will mentioned the purpose of this code and sample of this code for transmit in any direction.