EXAMPLES OF MEMORY INTERFACING (Contd..)
EXAMPLE-3
Consider a system in which 32kb memory space is implemented using four numbers of 8kb memory. Interface the EPROM and RAM with 8085 processor.
- The total memory capacity is 32Kb. So, let two number of 8kb n memory be EPROM and the remaining two numbers be RAM.
- Each 8kb memory requires 13 address lines and so the address lines A0- A12 of the processor are connected to 13 address pins of all the memory.
- The address lines and A13 - A14 can be decoded using a 2-to-4 decoder to generate four chip select signals.
- These four chip select signals can be used to select one of the four memory IC at any one time.
- The address line A15 is used as enable for decoder.
- The simplified schematic memory organization is shown.
Fig - Interfacing 16Kb EPROM and 16Kb RAM with 8085
