Hi, I Have a relatively big (14K), program that I try to debug. One of the functions reads an I2C peripheral memory (bit banged) there is no interrupt related to this function or other running functions. when I program the code(14K)into my chip AT89C51RD2 It works and diaplays the result, but using Mon51, it dosn't! It reads all 0xFF from I2C peripheral memory. the irony is when the same function is in a light (<4K) project like hello world it works with mon51. regards