I'm here to teach you how to fully understand the memory
ram ramdom access memoryRandom access memory, can be read and written quickly, but lost when power off
sramstatic ram Static random access memory, no need to refresh, high performance, large size, low integration, such as cpu cache
dramdynamic ram Dynamic random access memory, which needs to be refreshed, such as computer memory
sdramsynchronous dram Synchronous dynamic random access memory, ddr memory stick, sdram ddr, sdram ddr2 sdram ddr3
psram pseudo sram Pseudo-static random access memory, with its own refresh, the same interface as sram, low power consumption, capacity larger than sram but smaller than sdram, support burst mode
nvramnon-volatile ram Non-volatile random access memory, approved to save data after power failure
romread only memory Read-only memory, slow read and write speed, but can save data when power off
prom program rom Programmable read-only memory, programmable only once
epromerasable prom Erasable Programmable ROM, Requires Light Erasing
eepromelectric eprom Electrically erasable programmable read-only memory
flash flash eeprom can erase and read data quickly, also known as flash memory, u disk and mp3, bootloader memory, replacing eeprom
norflash nor falsh There is sram inside, which belongs to nvram. It has high transmission speed and can run applications directly. It can be run without transferring to ram. The writing and erasing speed is low. It needs to be set to zero before erasing. nand big
nandflash nand flash High storage density, easy to erase, much faster to erase and write than nor, but requires a special system interface unit
emmc nand + main control ic+mmc card for easy development