I am using the atmel 89ls53 microcontroller and am trying to access memory mapped devices(LCD,Flash card). I am using a 74hc573 to latch the address, but when i hook the address/data bus up to a logic analyzer, the add/data bus is putting out FFh all the time. I can write a pattern to P0 directly, but when i try to write externally nothing happens. Any help would be appreciated.