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Lecture on Hardware Specifications and Memory Interface. Presented By WWW.AssignmentPoint.Com. 8086 Microprocessor. 8088 Microprocessor. 8.1: Barry B. Brey. Chapter 9: Memory Interface. Address Pins. 1K Memory has A 0 – A 9 4K Memory has A 0 – A 11. Output/Data Pins.
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Lecture on Hardware Specifications and Memory Interface Presented By WWW.AssignmentPoint.Com www.assignmentpoint.com
8086 Microprocessor 8088 Microprocessor 8.1: Barry B. Brey www.assignmentpoint.com
Chapter 9: Memory Interface Address Pins • 1K Memory has A0 – A9 • 4K Memory has A0 – A11 Output/Data Pins • O0 – O7 for 8 bit computer • O0 – O15 for 16 bit computer www.assignmentpoint.com
Address Decoding • Why need address decoding? • 8086/8088 has 20 address pins • But EPROM, the memory device has less space • For example, 2716 EPROM is a 2K memory device www.assignmentpoint.com
NAND Gate Decoder 1111 1111 1000 0000 0000 = FF800H 1111 1111 1111 1111 1111 = FFFFFH • Decode memory address locations FF800H – FFFFFH Figure: 9-12 www.assignmentpoint.com
More Example • Develop a NAND gate decoder so that it decodes the memory range DF800H – DFFFFH www.assignmentpoint.com
The 3-to-8 Line Decoder (74LS138) www.assignmentpoint.com
Develop a 64K memory bank using eight 2764 EPROMs, where each 2764 EPROM is a 8K memory device and it address the memory locations F0000H – FFFFFH • 0000 0000 0000 0000 = F0000H • 1111 0001 1111 1111 1111 = F1FFFH • 0010 0000 0000 0000 = F2000H • 1111 0011 1111 1111 1111 = F3FFFH • 0100 0000 0000 0000 = F4000H • 1111 0101 1111 1111 1111 = F5FFFH • 0110 0000 0000 0000 = F6000H • 1111 0111 1111 1111 1111 = F7FFFH • 1000 0000 0000 0000 = F8000H • 1111 1001 1111 1111 1111 = F9FFFH • 1110 0000 0000 0000 = FE000H • 1111 1111 1111 1111 1111 = FFFFFH * * www.assignmentpoint.com
0000 0000 0000 0000 = F0000H • 1111 0001 1111 1111 1111 = F1FFFH • 0010 0000 0000 0000 = F2000H • 1111 0011 1111 1111 1111 = F3FFFH • 0100 0000 0000 0000 = F4000H • 1111 0101 1111 1111 1111 = F5FFFH • 0110 0000 0000 0000 = F6000H • 1111 0111 1111 1111 1111 = F7FFFH • 1000 0000 0000 0000 = F8000H • 1111 1001 1111 1111 1111 = F9FFFH • 1110 0000 0000 0000 = FE000H • 1111 1111 1111 1111 1111 = FFFFFH * * www.assignmentpoint.com
A13 A14 A15 A16 A17 A18 A19 www.assignmentpoint.com