Hardware platform: STM32F4 DISCOVERY development board Model: MB997A or MB997C
Main chip model: STM32F405xx, STM32F407 xx, STM32F415xx, or STM32F417xx
Main reference documents:
(1) PM0081 STM32F40xxx and STM32F41xxx Flash programming manual.pdf
(2) STM32F407 datasheet.pdf
As an embedded developer, after getting a chip, we first look at its parameter indicators, how much capacity of RAM, how much capacity of Flash. Of course, the premise is that the chip comes with these two modules.
Today we only study the structure of Flash :)
(1) It is stated that the flash modules of STM32F405xx, STM32F407xx, STM32F415xx, and STM32F417xx are the same, so we will use STM32F4 to represent them later in the article.
(B) Overview First, let ’s take an overview
2.1 Main memory
The addition of the Sectors in the main memory part is finally equal to 1024Kbyte, which is also consistent with the Capacity up to 1 Mbyte stated at the beginning of the document. In this area, we mainly store the programs written by our users. Here you may see that the address of the storage area starts from 0x08000000, which is why when we use the ST-Link2 programming program, we must specify the start The address is 0x08000000.
2.2 System memory
The System memory area is a reserved area of ​​the system and is used to start the chip in the "System memory boot" mode. It stores a special program called bootloader. By running the program in this area, the main memory can be reprogrammed. For example, if we choose to boot in System memory boot mode and plug in a USB flash drive with system firmware, then after configuration, the bootloader can read the firmware in the USB flash drive and burn it into the Main memory area. , How about, convenient! In other words, the firmware can be reprogrammed to the chip through USB OTG FS! Magical function :)
2.3 OTP area
This area is even more magical. OTP is the abbreviation of One-TIme programmable. It can be seen literally that this area is a one-time programming area. However, when wise humans also make mistakes, what if they are wrong! ST Company takes this into consideration. The 16 bytes starting from the address 0x1FFF7A00 are bytes with the "lock" function. When you are sure that the data written in the OTPx area is indeed correct, you can write to the LOCKBx address. 0x00, the OTPx area cannot be changed since then.
2.4 OpTIon bytes
The official document should be written wrong, how can 0x1FFFC000-0x1FFFC00F be 16Kbytes? It should be 16 bytes, right?
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