Some basic knowledge about SPI-Flash

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Some basic knowledge about SPI-Flash [Copy link]

1. Different SPIFLASH chips may provide the following erasing modes: sector erase (4KBytes), half block erase (32KBytes), block erase (64KBytes), and chip erase.

2. Different SPIFLASH chips may provide programming methods (that is, writing data): page programming (256Bytes), sector programming (4KBytes).

3. If SPIFLASH has been erased, it makes little sense to write data such as 0xFF into it, because its characteristic is that the data after erasure is 0xFF.

4. When writing to flash, you can only change the data (bit) from 1 to 0.

5. The characteristic of traditional EEPROM is that any byte can be randomly accessed and modified, and 0 or 1 can be written to each bit. When writing to flash, data (bit) can only be changed from 1 to 0. However, the capacity of traditional EEPROM is limited due to cost, and rarely exceeds 512K.

6.Nor Flash has a relatively small capacity and high cost. It has almost no bad blocks. The data line and address line are separated, which can realize random addressing and read any byte. However, erasing still needs to be done by block. NAND FLASH has a large capacity and low cost. Bad blocks often appear, but they can be marked so that the software can skip them. The data line and address line are reused, and the data can be erased by block and read by page.