SAM3S_14 Datasheet, PDF (167/1087 Pages) ATMEL Corporation – AT91SAM ARM-based Flash MCU

WO
Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is
Unpredictable.
• VECTRESET
WO
Reserved for Debug use. This bit reads as 0. When writing to the register you must write 0 to this bit, otherwise behavior is
Unpredictable.
11.20.6.1 Binary point
The PRIGROUP field indicates the position of the binary point that splits the PRI_n fields in the Interrupt Priority
Registers into separate group priority and subpriority fields. Table 11-31 shows how the PRIGROUP value controls
this split.
Table 11-31. Priority grouping
Interrupt priority level value, PRI_N[7:0]
Number of
Binary
PRIGROUP point ⁽¹⁾
Group priority Subpriority
bits
bits
Group
priorities
Subpriorities
b011
bxxxx.0000
[7:4]
None
16
1
b100
bxxx.y0000
[7:5]
[4]
8
2
b101
bxx.yy0000
[7:6]
[5:4]
4
4
b110
bx.yyy0000
[7]
[6:4]
2
8
b111
b.yyyy0000
None
[7:4]
1
16
1.
PRI_n[7:0] field showing the binary point. x denotes a group priority field bit, and y denotes a sub-
priority field bit.
Determining preemption of an exception uses only the group priority field, see “Interrupt priority grouping” on page
64.
SAM3S [DATASHEET]
6500E–ATARM–11-Feb-13
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