DDR基础学习（1）--内存容量计算
以镁光DDR为例，对DDR进行容量计算，
DDR/DDR2/DDR3 颗粒容量 = Column * Row * BANK * 芯片位宽
DDR4/LPDDR4 颗粒容量=Column * Row * BANK * 芯片位宽*BANK groups
1 die=颗粒容量
2 die=颗粒容量*2
4 die=颗粒容量*4
DDR SDRAM----256Mb
颗粒容量 = Column * Row * BANK * 芯片位宽
= 2^9 * 2^13 * 2^2 * 16
= 2^28 bit
= 2^8 *1024*1024
= 256 Mb
DDR2 SDRAM----2Gb
颗粒容量 = Column * Row * BANK * 芯片位宽
= 2^10 * 2^14 * 2^3 * 16
= 2^31 bit
= 2 * 1024*1024*1024
= 2Gb
DDR3 SDRAM----2Gb
颗粒容量 = Column * Row * BANK * 芯片位宽
= 2^10 * 2^14 * 2^3 * 16
= 2^31 bit
= 2 * 1024*1024*1024
= 2Gb
DDR4 SDRAM----16Gb
颗粒容量 = Column * Row * BANK * 芯片位宽 * BANK groups
= 2^10 * 2^17 * 2^2 * 16 * 2
= 2^34 bit
= 16 * 1024*1024*1024
= 16Gb
LPDDR4 SDRAM--16Gb
颗粒容量 = Column * Row * BANK * 芯片位宽 * Die number
= 2^10 * 2^16 * 2^3 * 16 * 2
= 2^34 bit
= 16 * 1024*1024*1024
= 16Gb
