Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
214
12.9.1.5 Application Interrupt and Reset Control Register
Name:
SCB_AIRCR
Access:
Read
/Write
Reset:
0x00
0000000
The SCB_AIRCR provides priority grouping control for the exception model, endian status for data accesses, and reset
control of the system. To write to this register, write 0x5FA to the VECTKEY field, otherwise the processor ignores the
write.
• VECTKEYSTAT: Register Key
Read:
Reads as 0xFA05.
Reads as 0xFA05.
• VECTKEY: Register Key
Write:
Writes 0x5FA to VECTKEY, otherwise the write is ignored.
Writes 0x5FA to VECTKEY, otherwise the write is ignored.
• ENDIANNESS: Data Endianness
0: Little-endian.
1: Big-endian.
• PRIGROUP: Interrupt Priority Grouping
This field determines the split of group priority from subpriority. It shows the position of the binary point that splits the PRI_n
fields in the Interrupt Priority Registers into separate group priority and subpriority fields. The table below shows how the
PRIGROUP value controls this split.
31
30
29
28
27
26
25
24
VECTKEYSTAT/VECTKEY
23
22
21
20
19
18
17
16
VECTKEYSTAT/VECTKEY
15
14
13
12
11
10
9
8
ENDIANNESS
–
PRIGROUP
7
6
5
4
3
2
1
0
–
SYSRESETREQ VECTCLRACTI
VE
VECTRESET
PRIGROUP
Interrupt Priority Level Value, PRI_N[7:0]
Number of
Binary Point
Group Priority Bits
Subpriority Bits
Group Priorities
Subpriorities
0b000
bxxxxxxx.y
[7:1]
None
128
2
0b001
bxxxxxx.yy
[7:2]
[4:0]
64
4
0b010
bxxxxx.yyy
[7:3]
[4:0]
32
8
0b011
bxxxx.yyyy
[7:4]
[4:0]
16
16
0b100
bxxx.yyyyy
[7:5]
[4:0]
8
32