1. Memory Organization and Interfacing CSE 2312 Maher Al-Khaiyat

2. Semiconductor Memory Capacity Capacity Kbits (Kilobits)Kbits (Kilobits) Mbits (Megabits)Mbits (Megabits) Organization Organization Number of locations => Number of address linesNumber of locations => Number of address lines Size of a location => Number of data linesSize of a location => Number of data lines

3. Semiconductor Memory (cont’d) Speed Speed Access timeAccess time Volatility Volatility Programmability Programmability

4. Memory Organization Number of locations Number of address lines Number of data lines

5. Nonvolatile Memory Read-Only Memory (ROM) Read-Only Memory (ROM) Programming or Burning Programming or Burning PROM; one-time programmablePROM; one-time programmable EPROM; erasable using UV radiationEPROM; erasable using UV radiation EEPROM; electrically erasableEEPROM; electrically erasable Flash ROM; erasable in a flash (fast time)Flash ROM; erasable in a flash (fast time) Mask ROM; mask technologyMask ROM; mask technology

6. Volatile Memory Random Access Memory (RAM) Random Access Memory (RAM) Types Types Static RAM (SRAM)Static RAM (SRAM) does not require refreshing does not require refreshing up to four transistors per cell up to four transistors per cell Dynamic RAM (DRAM)Dynamic RAM (DRAM) requires refreshing requires refreshing one transistor (capacitor) per cell one transistor (capacitor) per cell

7. Address Decoding 32Kx8 A0 A14 OE WR MEMR MEMW CS D7D0 A15 A16 A17 A18 A19 00001000000000000000 00001111111111111111 A0A19 Range of addresses 08000h to 0FFFFh … … …

8. Conventional Memory 640K of RAM 640K of RAM ROM 256K VDR 128K RAM 640K 00000h 9FFFFh A0000h BFFFFh C0000h FFFFFh Conventional memory MS-DOS OS Utilities Applications Etc… 003FFh 004FFh Interrupt vector table BIOS temp data

9. BIOS Data Area Start Address End Address # Bytes Description 0000:00000000:03FF1024 Interrupt table 0000:04000000:04012 Port address COM1 ………… 0000:04080000:04092 Port address LPT1 ….….…… 0000:04100000:04112 List of hardware 0000:004120000:04121 Initialization flag 0000:04130000:04142 Memory size (KB) ………… …………

10. DRAM Memory Banks 64K x 4 64K x 1 Bank 3 64K x 4 64K x 1 Bank 2 256K x 4 256K x 1 Bank 1 256K x 4 256K x 1 Bank 0 Example configuration of 640KB RAM