1. Memory Basics
Chapter 8

2. Memory definitions
RAM
Random access memory
ROM
Read-only memory

3. RAM

4. Control inputs to a memory chip

5. Properties of memory Static RAM (SRAM) Dynamic RAM (DRAM)
Consists of internal latches that store the binary information
Dynamic RAM (DRAM)
Stores the binary information in the form of electric charges on capacitors

6. 若Bit select為1，則接通1, 2 gates。 𝑊𝑟𝑖𝑡𝑒 為1，寫入資料，3, 4接通。Data in之後產生B, 𝐵 ，再選word，選到的5,6,7,8接通，此時不是Set就是Reset，傳入C或 𝐶 。在Read logic S, R其一為1，經2輸出。

7. Three-state buffer IN EN
OUT EN IN
OUT X
Hi-Z 1
16-word by 1-bit
RAM chip

8. 16x1 RAM using a
4x4 RAM cell array
Reduce number of
Decoder gates
Inputs per gate
RAM cells per slice

9. 8x2 RAM using a
4x4 RAM cell array

10. Example A 32K x 8 RAM 32K x 8=215*23=218 Each column 29 9-29 decoder
6-26
decoder

11. 64K x 8 RAM

12. 256K x 8 RAM

13. 64K x 16 RAM