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/
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Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Boot configuration
In addition, SRAM can also be accessed through virtual address segment 0x1000_0000, which makes the CPU jump
to SRAM to run programs through ICode/DCode after starting from Main Flash or System Memory (note that
programs are not started from SRAM and do not belong to startup mode). In addition to the BOOT pin configuration
boot program, there are two ways to run the program in SRAM:
Jump directly to the physical address segment 0x2000_0000 of SRAM to run the program. At this time, the
program will be run through SBus.
Jump to the virtual address segment 0x1000_0000 of SRAM, and internally remap to the physical address
segment 0x2000_0000 to run the program. At this time, the program will run efficiently through ICode/DCode.
Table 3-1 List of boot mode
Boot mode select
pin
Boot mode
Specifies the start address for accessing memory space in boot mode
BOOT1
BOOT0
Main Flash
System Memory
SRAM
X
0
Mian Flash start
0x0000_0000
0x0800_0000
0x1FFF_0000
0x1000_0000
0x2000_0000
0
1
System Memory
start
0x08000000
0x0000_0000
0x1FFF_0000
0x1000_0000
0x2000_0000
1
1
SRAM start
0x08000000
0x1FFF_0000
0x0000_0000
0x1000_0000
0x2000_0000
Embedded boot loader
Embedded boot loader program is stored in the system memory System Memory and is used to reprogram the flash
memory through the USART1 or USB-FS interface (full-speed USB device, DFU protocol). The USB-FS interface
can only be run when the external clock (HSE) of 4MHz, 6MHz, 8MHz, 12MHz, 16MHz, 18MHz, 24MHz and
32MHz is used. In addition to the above-mentioned 8-frequency external clock (HSE), the USART1 interface can
also rely on the internal 8MHz oscillator (HSI) to run. Consult the bootloader manual for further details.
Memory system
The program memory, data memory, registers and I/O ports are organized in the same 4GB linear address space. Data
bytes are stored in the memory in little endian format. The lowest address byte in a word is regarded as the least
significant byte of the word, while the highest address byte is the most significant byte. The specifications of program
memory and data memory are as follows.
3.2.1
FLASH specification
Flash consists of a main storage area and an information area, which are described separately below: (Capacity values
in the following description do not include ECC)
The maximum main memory area is 512KB, also known as main flash memory, which contains 256 Page for
storing and running user programs and storing data.