课件：数字逻辑5-3(1).ppt

1、Memory blocksCHAPTER 5 Design by IC blocks Memory Memory Read only memory(ROM)Mask ROM:use a diode or transistor as memory connection.P-ROM:Programmable,add a fuse to the device.Read only memory(ROM)EPROM:Erasable PROM,use floating-gate technology.Include EEPROM and FLASH.Read only memory(ROM)Static

2、 RAM (SRAM)The memory device is a latch,the data is stable,and the access time is short,but the circuit is complex and expensive!Dynamic RAM (DRAM)The memory device is capacitor Very simple,high density;The output signal is very weak,a sense amplifier is needed;The data stored need to refresh period

3、ically!Memory IC:ROM If there are N address input,2N word can be stored;CS and OE port can be used for expand the memory.Memory IC:RAM Use WE port to control data input/output!Expansion for Memory ICExpansion for Memory ICMemory Data bits are stored in a structured wayOnce a word line is selected,all the bits in this line can be output through the bit lines!Example:When a2a1a0=000,y4y3y2y1=1000;When a2a1a0=101,y4y3y2y1=0110;Memory Programmable logic deviceA truth table is stored in the memory array!Each bit line is a function output!