Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
6
/
631
Address range
Peripherals
Bus
0x4000_2000 – 0x4000_23FF
OPAMP
0x4000_1C00 – 0x4000_1FFF
Reserved
0x4000_1800 – 0x4000_1BFF
Reserved
0x4000_1400 – 0x4000_17FF
TIM7
0x4000_1000 – 0x4000_13FF
TIM6
0x4000_0C00 – 0x4000_0FFF
TIM5
0x4000_0800 – 0x4000_0BFF
TIM4
0x4000_0400 – 0x4000_07FF
TIM3
0x4000_0000 – 0x4000_03FF
TIM2
Bit banding
Cortex™-M4FP memory image includes two bit-band areas. These two bit-band areas map each word in the alias
memory area to a bit in the bit-band memory area. When writing a word in the alias area, it is equivalent to performing
a read-modify-write operation on the target bits of the bit segment area.
Both the peripheral registers and SRAM are mapped into a bit-band area, which allows a single bit-band area write
and read operation to be performed.
The following mapping formula shows how each byte in the alias area corresponds to the corresponding bit in the bit
band area:
bitband_ byte _addr = bitband _base + (byte_offset×32) + (bit_number×4)
In which:
bitband_byte_addr is the address of the byte in the alias memory area, which is mapped to a certain target bit;
bitband _base is the starting address of alias area;
byte_offset is the serial number of the byte containing the target bit in the bit-band;
bit_number is the position of the target bit (0-7).
For example:
The following example shows how to map bit 4 in bytes with SRAM address 0x20000400 in alias area:
0x22008010 = 0x22 (0x400×32) + (4×4).
Writing to address 0x22008010 has the same effect as reading-modify-writing to bit 4 of address 0x20000400 bytes
in SRAM.
Reading 0x22008010 address returns the value of bit 4 (0x01 or 0x00) of address 0x20000400 bytes in SRAM. Please
refer to “Cortex™-M4 Technical Reference Manual” for more information about bit-banding.
Boot management
Boot address
During system startup, you can select the BOOT mode after the reset through the BOOT0 pin and the user option