AT32F421
Series Reference Manual
2022.11.11
Page 29
Rev 2.02
0x2000_0004.2
0x2200_0088.0
…
…
0x200F_FFFC.31
0x23FF_FFFC.0
shows the mapping between bit-band region and alias region in the peripheral area:
Table 1-2 Bit-band address mapping in the peripheral area
Bit-band region
Equivalent alias address
0x4000_0000.0
0x4200_0000.0
0x4000_0000.1
0x4200_0004.0
0x4000_0000.2
0x4200_0008.0
…
…
0x4000_0000.31
0x4200_007C.0
0x4000_0004.0
0x4200_0080.0
0x4000_0004.1
0x4200_0084.0
0x4000_0004.2
0x4200_0088.0
…
…
0x400F_FFFC.31
0x43FF_FFFC.0
In addition, bit-band operations can also simplify jump process. When jump operation is based on a bit
level, the previous steps are:
Read the whole register
Mask the undesired bits
Compare and jump
For now, you just need do:
Read the bit status from the bit-band alias region
Compare and jump
Apart from making code more concise, its important function is also reflected in multi-task environment.
When it comes to multiple tasks, it turns the read-modify-write operations into a hardware-supported
atomic operation to avoid the scenario where the read-modify-write operation is disrupted, resulting in
disorder.
1.1.3
Interrupt and exception vectors
Table 1-3 AT32F421 series vector table
Pos. Priority
Priority
Type
Name
Description
Address
-
-
-
Reserved
0x0000_0000
-3
Fixed
Reset
Reset
0x0000_0004
-2
Fixed
NMI
Non maskable interrupt
CRM clock fail detector (CFD) is linked to
NMI vector
0x0000_0008
-1
Fixed
HardFault
All class of fault
0x0000_000C
0
Configurable MemoryManage Memory management
0x0000_0010
1
Configurable
BusFault
Pre-fetch fault, memory access fault
0x0000_0014