Semiconductor memory refers to semiconductor integrated memory, which is a solid state electronic device made of semiconductor integrated circuit technology to store data and information. It is generally composed of a large number of identical memory units and input and output circuits. Today we will talk about the classification of semiconductor memory.

First of all, according to the function can be divided into read-only memory and random access memory two categories. Read-only memory literally means that you can only read from the inside. Just like a book, you can only read from the inside. You can't    change the contents of the book. 

Random access memory, that is, you can rewrite it at any time, you can read it out, it's like our blackboard, you can write something on it at any time, you can erase it with an eraser and you can rewrite it. 

In addition, semiconductor memory can be further subdivided into the following four types by extension:

PROM, called programmable memory. This is like our exercise book, bought when it is blank, can write things up, but once written up, it can not be erased, so it can only be written once, if written wrong, reimbursed, now basically eliminated.

EPROM, called ultraviolet erasure programmable read-only memory. After it is written up, if you feel dissatisfied, you can use a special way to remove and rewrite it, which is to use ultraviolet light, ultraviolet light is like "the spirit of the word",    can remove the word, and then rewrite it. Of course, the number of erasers is too much, so the number of erasers that this chip can erase is also limited to about a few hundred times.

EEPROM, also known as E2PROM, is called electrically erasable programmable read-only memory. It is similar to EEPROM in that things written on it can also be erased and rewritten, but it is more convenient. There is no need for light.

FLASH, known as flash memory, is an improved product of EEPROM. Its biggest characteristic is that it must be erased by Block (the size of each block is variable, different manufacturers have different specifications), while EEPROM can erase only one    Byte at a time. FLASH is now commonly used for mass storage, such as USB sticks.

It is important to note that all writing does not refer to normal working conditions. Whether PROM or EPROM, they have to be written under special conditions. We usually use a device called a "programmer" to do this work. Once it is installed in its working    position, it cannot be written at will.

The above is about Yufan micro engineers for semiconductor memory all content to share, after reading we must have a deeper understanding. Yufan micro provides ic wafer production and packaging customization, as a nine level agent, has more than 10 years    of SCM chip application design experience, for the majority of electronic products manufacturers to provide MCU application function customization development services.