Lecture on Hardware Specifications and Memory Interface Presented
- Slides: 10
Lecture on Hardware Specifications and Memory Interface Presented By WWW. Assignment. Point. Com www. assignmentpoint. com
8086 Microprocessor 8088 Microprocessor www. assignmentpoint. com 8. 1: Barry B. Brey
Chapter 9: Memory Interface Address Pins • 1 K Memory has A 0 – A 9 • 4 K Memory has A 0 – A 11 Output/Data Pins • O 0 – O 7 for 8 bit computer • O 0 – O 15 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 2 K memory device www. assignmentpoint. com
NAND Gate Decoder • Decode memory address locations FF 800 H – FFFFFH 1111 1000 1111 0000 1111 = = FF 800 H FFFFFH Figure: 9 -12 www. assignmentpoint. com
More Example • Develop a NAND gate decoder so that it decodes the memory range DF 800 H – DFFFFH www. assignmentpoint. com
The 3 -to-8 Line Decoder (74 LS 138) www. assignmentpoint. com
• Develop a 64 K memory bank using eight 2764 EPROMs, where each 2764 EPROM is a 8 K memory device and it address the memory locations F 0000 H – FFFFFH 1111 0000 = F 0000 H 1111 0001 1111 = F 1 FFFH 1111 0010 0000 = F 2000 H 1111 0011 1111 = F 3 FFFH 1111 0100 0000 = F 4000 H 1111 0101 1111 = F 5 FFFH 1111 0110 0111 1000 1001 0000 1111 0000 1111 = = F 6000 H F 7 FFFH F 8000 H F 9 FFFH * * 1111 1110 0000 = FE 000 H 1111 1111 = FFFFFH www. assignmentpoint. com
1111 0000 = F 0000 H 1111 0001 1111 = F 1 FFFH 1111 0010 0000 = F 2000 H 1111 0011 1111 = F 3 FFFH 1111 0100 0000 = F 4000 H 1111 0101 1111 = F 5 FFFH 1111 0110 0111 1000 1001 0000 1111 0000 1111 = = F 6000 H F 7 FFFH F 8000 H F 9 FFFH * * 1111 1110 0000 = FE 000 H 1111 1111 = FFFFFH www. assignmentpoint. com
A 13 A 14 A 15 A 16 A 17 A 18 A 19 www. assignmentpoint. com