Table 5.1 Semiconductor Memory Types Memory Type Category Erasure Write Mechanism Volatility Random-access memory (RAM) Read-write memory Electrically, byte-level Electrically Volatile Read-only memory (ROM) Masks Programmable ROM (PROM) Read-only memory Not possible Erasable PROM (EPROM) UV light, chip-level Electrically Erasable PROM (EEPROM) Electrically, byte-level Flash memory Read-mostly memory Electrically, block-level Electrically NonvolatileTable 5.2 Increase in Word Length with Error Correction Single-Error Correction Single-Error Correction/ Double-Error Detection Data Bits Check Bits % Increase Check Bits % Increase 8 4 50 5 62.5 16 5 31.25 6 37.5 32 6 18.75 7 21.875 64 7 10.94 8 12.5 128 8 6.25 9 7.03 256 9 3.52 10 3.91Table 5.3 Performance Comparison of Some DRAM Alternatives Clock Frequency (MHz) Transfer Rate (GB/s) Access Time (ns) Pin Count SDRAM 166 1.3 18 168 DDR 200 3.2 12.5 184 RDRAM 600 4.8 12 162Table 5.4 SDRAM Pin Assignments A0 to A13 Address inputs CLK Clock input CKE Clock enable Chip select RAS Row address strobe CAS Column address strobe WE Write enable DQ0 to DQ7 Data input/output DQM Data
View Full Document
Unlocking...