Nations Technologies Inc.
Tel
:
+86-755-86309900
:
info@nationstech.com
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
8
/
631
Boot mode select pin
Boot mode
Specifies the start address for accessing
memory space in boot mode
nBOOT1
nBOOT0
BOOT0 pin
nSWBOOT0
Main Flash
System
Memory
SRAM
0
X
1
1
SRAM start
0x08000000
0x1FFF_0000
0x0000_0000
0x2000 0000
0x1000 0000
0
0
X
0
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 16MHz oscillator (HSI) to run.
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.
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 128KB, also known as main flash memory, which contains 64 Page for
storing and running user programs and storing data.
The information area is 20KB, including 10 Page, and consists of system storage area (16KB), system
configuration area (2KB) and option byte area (2KB).
The System Memory area is 16KB, which contains 8 Page, also known as System Memory, and is used to
store and run the BOOT program.
The system configuration area is 2KB, including 1 Page.
The Option Byte area is 2KB, containing 1 Page, also known as Option Byte, and the effective space is
20B, BOOT programs and user programs can be read, written or erased.
Flash memory module organization
Bus address space is allocated to the main storage area and the information area.