The difference between Flash and EEPROM (reprint)Flash and EEPROM The biggest difference is the flash by sector operation, EEPROM operation by Byte, the two addressing methods are different, the structure of the storage unit is also different, FLASH circuit structure is simpler, the same capacity for the chip area is small, the cost is naturally lower than EEPROM, Therefore, it is suitable for use as program memory, and EEPROM is more used as nonvolatile data memory. Of course, using Flash to do the data memory, but the operation is more troublesome than EEPROM, so more "humanized" MCU design will be integrated flash and EEPROM two nonvolatile memory, and inexpensive design often only flash, the early electro-writable MCU is the EEPRM structure, It is now largely discontinued. In the chip of the circuit, Flash and EEPROM not only the circuit, address space is also different, operating methods and instructions are also different, regardless of the von Neumann structure or the Harvard structure is the case. Technically, the program memory and non-volatile data memory can be used only FALSH structure or EEPROM structure, even with "flexible" technical means in the program store Simulation "data store", but even so, the concept is still different, this is the basic common sense problem. EEPROM: Electric erasable Programmable read-only memory, flash operation characteristics fully conform to the definition of EEPROM, is an EEPROM is undoubtedly, the first flash launched its data manual is also clearly marked as EEPROM, and now most flash manuals are so marked, The relationship between the two is "White Horse" and "horse". As for why the industry to distinguish between the two, the main reason is the Flash eeprom operation method and the traditional EEPROM is very different, the secondary reason is for the brevity of language, non-official documents and the Flash EEPROM in the spoken word is abbreviated as Flash, here to emphasize the white horse "white" attribute instead of its "horse" attribute to differentiate between flash and traditional EEPROM. The flash is characterized by a simple structure, the same process and the same wafer area can get higher capacity and large data volume of operation faster, but the disadvantage is that the operation process is cumbersome, especially when the small amount of data repeatedly rewritten, Therefore, the flash structure in the MCU is suitable for the program memory which does not need to be rewritten frequently. in many applications, the need to frequently rewrite some small amounts of data and the need to power off non-volatile, the traditional structure of the EEPROM is very suitable for this, so many MCU internal design of two EEPROM structure, Flash and traditional in order to get the balance of cost and function, which greatly facilitates the user. With the popularity of ISPs, IAP, especially in the MCU system where the program stores the address space and the data storage address space, more and more MCUs are producing commercial support IAP program memory to simulate the EEPROM corresponding data memory, which is a workaround for low cost non-volatile data memory. In order to obtain the "equivalent" of the dual-EEPROM process in the commercial propaganda, many use Flash program memory "simulation" (note that the technical concept is not true analog) EEPROM data memory manufacturers have claimed that their products are with EEPROM, strictly speaking, this is very not rigorous, But businessmen have the purpose and method of businessmen, using flash "simulation" EEPROM can gain greater commercial interests, so in fact, the technical concept of confusion is the initiator of them. from the cost of speaking, with flash "simulation" EEPROM is economical, the other hand will not be dry, using EEPROM to simulate how flash is going? This may be in some program storage space and data storage space on a continuous MCU. Such MCUs, especially low-end MCUs with little storage capacity, still use EEPROM as nonvolatile memory, which is less costly than the dual-process design of flash and traditional eeprom, but this phenomenon is limited to small capacity. Because of the popularity of Flash technology, now many businessmen and not rigorous technical staff will be called Flash Program memory, for those who only use the traditional EEPROM process MCU, they superficial understanding, so the wrong EEPROM program memory called "Analog Flash", The root cause is that they don't understand that Flash is just a memory structure, not a memory, and the wrong premise naturally leads to the wrong conclusion. Commercially speaking, using EEPROM to simulate flash is a foolish act that no one really does, which is contrary to the principle of commercial pursuit of the best interests, technically not feasible, and for technical personnel. The essence of the problem is that Flash is a type of memory rather than a program memory in the MCU, even though the MCU's program memory is flash, but its inverse proposition is not true.
The difference between Flash and EEPROM
