110 likes | 263 Views
Memory Organization and Interfacing. CSE 2312 Maher Al-Khaiyat. Semiconductor Memory. Capacity Kbits (Kilobits) Mbits (Megabits). Organization Number of locations => Number of address lines Size of a location => Number of data lines. Semiconductor Memory (cont’d). Speed Access time
E N D
Memory Organization and Interfacing CSE 2312 Maher Al-Khaiyat
Semiconductor Memory • Capacity • Kbits (Kilobits) • Mbits (Megabits) • Organization • Number of locations => Number of address lines • Size of a location => Number of data lines
Semiconductor Memory (cont’d) • Speed • Access time • Volatility • Programmability
Number of address lines Number of locations Number of data lines Memory Organization
Nonvolatile Memory • Read-Only Memory (ROM) • Programming or Burning • PROM; one-time programmable • EPROM; erasable using UV radiation • EEPROM; electrically erasable • Flash ROM; erasable in a flash (fast time) • Mask ROM; mask technology
Volatile Memory • Random Access Memory (RAM) • Types • Static RAM (SRAM) • does not require refreshing • up to four transistors per cell • Dynamic RAM (DRAM) • requires refreshing • one transistor (capacitor) per cell
D7 D0 32Kx8 A0 A15 A16 A14 A17 CS A18 A19 WR OE MEMW MEMR Address Decoding A19 A0 … … … Range of addresses 08000h to 0FFFFh
Conventional Memory • 640K of RAM FFFFFh ROM 256K C0000h BFFFFh VDR 128K A0000h • Conventional memory • MS-DOS OS • Utilities • Applications • Etc… 9FFFFh RAM 640K 004FFh BIOS temp data 003FFh Interrupt vector table 00000h
64K x 4 64K x 4 64K x 1 Bank 3 64K x 4 64K x 4 64K x 1 Bank 2 256K x 4 256K x 4 256K x 1 Bank 1 256K x 4 256K x 4 256K x 1 Bank 0 DRAM Memory Banks Example configuration of 640KB RAM