14_EEL4742-Notes#15

# 14_EEL4742-Notes#15 - EEL4742 Notes 15 Address Decoder and...

• Notes
• 3

This preview shows pages 1–3. Sign up to view the full content.

EEL4742 Notes # 15 Address Decoder and Decoding Typical memory interface The address decoder determines when the memory IC’s are accessed . ce R/W Function 1 x Hold/Standby 0 1 Read 0 0 Write Consider 16 Bit address lines A 0 -A 15 64K memory map. and 8K by 16 Bit memory I.C. The question is where to put the 8K memory in the 64K memory map . Where you place the 8K block of memory determines when the ce must go low. Some important #s 10 Bits = 1K 20 Bits = 1 Meg 30 Bits = 1 G. Also 1000h = 4096 100h = 256 Typically the memory IC’s are smaller than the memory space

This preview has intentionally blurred sections. Sign up to view the full version.

Consider just A 15 . If A 15 = 0 and A 0 - A 14 are allowed to change between all zeros and all ones , we have the addresses: 0000h 7FFF. If A 15 = 1, then we have the address 8000h FFFFh. So, A 15 divides the memory space into 2 blocks 32K each . A 15 = 0, lower 32K (0000h 7FFFh) and A 15 =1, the upper 32K (8000h FFFFh). Now consider A 15 A 14 if A 15 A 14 = 00 and A 0 - A 13 are allowed to change between all zeros and all ones, then addresses are from 0000h 3FFFh (this becomes a 16 bit block) A 15 A 14 =
This is the end of the preview. Sign up to access the rest of the document.
• Spring '11
• Weeks
• Power of two, 1 g, 1 byte, Howard Staunton, Riga, 2 Byte

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern