Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet
Product codes
ATSAM4E-XPRO
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
260
12.10.1.1 SysTick Control and Status
Name:
SYST_CSR
Access: Read/Write
Reset: 0x000000000
The SysTick SYST_CSR enables the SysTick features.
COUNTFLAG: Count Flag
Returns 1 if the timer counted to 0 since the last time this was read.
CLKSOURCE: Clock Source
Indicates the clock source:
0: External Clock.
1: Processor Clock.
TICKINT: SysTick Exception Request Enable
Enables a SysTick exception request:
0: Counting down to zero does not assert the SysTick exception request.
1: Counting down to zero asserts the SysTick exception request.
The software can use COUNTFLAG to determine if SysTick has ever counted to zero.
ENABLE: Counter Enable
Enables the counter:
0: Counter disabled.
1: Counter enabled.
When ENABLE is set to 1, the counter loads the RELOAD value from the SYST_RVR and then counts down. On reaching
0, it sets the COUNTFLAG to 1 and optionally asserts the SysTick depending on the value of TICKINT. It then loads the
RELOAD value again, and begins counting.
0, it sets the COUNTFLAG to 1 and optionally asserts the SysTick depending on the value of TICKINT. It then loads the
RELOAD value again, and begins counting.
31
30
29
28
27
26
25
24
–
23
22
21
20
19
18
17
16
–
COUNTFLAG
15
14
13
12
11
10
9
8
–
7
6
5
4
3
2
1
0
CLKSOURCE
TICKINT
ENABLE