Digital Electronics: Principles, Devices and Applications

Computer Fundamentals 637A 0 A 1 A 2 A 3 A 4 A 5 A 6 A 7 A 8 A 91K × 8CS1ROMCS2O 0 O 1 O 2 O 3 O 4 O 5 O 6 O 7Figure 15.25 Example 15.4.AB10Address BusAB9AB1AB0A 9 A 1 A 0A 9 A 1 A 0CS11K × 81K × 8ROM-1ROM-2'1'CS2CS1CS2D 7D 0D 7D 0Data BusFigure 15.26 Solution to example 15.4.• For an address input 00001101, RAM-1 and RAM-2 will be selected.• The address input range for which RAM-1 and RAM-2 are active is (00000000) 2 to (00001111) 2 .15.8 Input and Output PortsInput and output ports were briefly introduced in the earlier part of the chapter in Section 15.1.3.As outlined earlier, these are categorized as serial and parallel ports. The commonly used serial andparallel ports are described in the following paragraphs.