ram memory 4gb What do nouns in DDR mean Noun parsing in DDR【Details】

ram memory 4gb What do nouns in DDR mean Noun parsing in DDR【Details】

solid state driveSSD OEM ram memory 4gb RAS: Row Address Stroberammemory 4gb, line address strobe pulse;

CAS: Column Address Stroberam memory 4gb, column address strobe pulse;

tRCD: RAS to CAS Delay, RAS to CAS delay;

CL: CAS Latency, CAS latency (also known as read latency), the period of time from the time the CAS and read commands are issued to the first data output;

RL: Read Latency, read latency;

tAC: Access Time from CLK, access time after clock triggering, from the time of the rise edge of the clock before the data output on the data I/O bus to the point when the data is passed on the I/O bus;

tWR: Write Recovery Time, writeback, which ensures reliable write-to-data and allows sufficient write/correction time, is used to indicate the amount of time between the last valid operation on the same bank and the precharge command;

BL: Burst Lengths, burst lengths, burst refers to the continuous data transmission of adjacent storage units in the same row, the number of storage units (columns) involved in continuous transmission is the burst length (SDRAM), in DDR SDRAM refers to the number of consecutive transmission cycles;

Precharge:L-Bank closes the existing working line and prepares to open a new line;

tRP: Precharge command period, precharge valid period, after issuing the precharge command, it takes a period of time to allow the RAS line valid command to be sent to open a new working line;

AL: Additive Latency, with additional latency (DDR2);

WL: Write Latency, the latency of the write command issued to the first data input;

tRAS: Active to Precharge Command, valid until the precharge command interval cycle;

tDQSS: WRITE Command to the first corresponding rising edge of DQS, the latency of DQS relative to write commands;

Logical Bank

The interior of SDRAM is a storage array, in order to accurately find the desired storage unit, first specify a row (row), and then specify a column (Column), which is the basic principle of memory chip addressing.

chip bit width The amount of data in the SDRAM memory chip transfer rate is the chip bit width, then the capacity of this memory unit is the bit width of the chip (also the bit width of L-Bank);

The number of storage units = number of rows * number of columns (to obtain the number of storage units of an L-Bank) * The number of L-banks can also be expressed in the form of M*W, M is the total number of storage units in the chip, the unit is megabytes (English abbreviation M, the exact value is 1048576), W represents the capacity of each storage unit, that is, the bit width of the SDRAM chip, the unit is bit;

DDR SDRAM internal memory cell capacity is double the chip bit width (chip I/O port width);

DDR2 SDRAM internal memory unit capacity is four times the chip bit width;

DDR3 SDRAM internal memory unit capacity is eight times the chip bit width;

DDR4 SDRAM internal memory unit capacity is eight times the chip bit width.” solid state driveSSD OEMram memory 4gb