I need you generous help, Folks. The following is part of my code. What I want to do is to check if the bus is free, if it is, then I want to read out the data at the address 0. "Address 0" means page0 and word address also is 0. "RECACK_MEMO()" works well in "WR_MEMO". WR_MEMO( 3, 0 ); if ( RECACK_MEMO() == 1 ) { RD_MEMO( 0 ); } But why this program keeps checking at " if " sentence ( more than 10 seconds)and does not go further?