SAM3N00A Atmel Corporation, SAM3N00A Datasheet - Page 192

• Manufacturer Part Number: SAM3N00A
• Manufacturer: Atmel Corporation

10.22.1
• COUNTFLAG
Returns 1 if timer counted to 0 since last time this was read.
• CLKSOURCE
Indicates the clock source:
0 = MCK/8
1 = MCK
• TICKINT
Enables SysTick exception request:
0 = counting down to zero does not assert the SysTick exception request
1 = counting down to zero to asserts the SysTick exception request.
Software can use COUNTFLAG to determine if SysTick has ever counted to zero.
• ENABLE
Enables the counter:
0 = counter disabled
1 = counter enabled.
When ENABLE is set to 1, the counter loads the RELOAD value from the LOAD register and then counts down. On reach-
ing 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.
192
31
23
15
7
SAM3N
SysTick Control and Status Register
30
22
14
6
The SysTick CTRL register enables the SysTick features. See the register summary in
33 on page 191
Reserved
29
21
13
5
for its attributes. The bit assignments are:
Reserved
28
20
12
4
Reserved
Reserved
27
19
11
3
CLKSOURCE
26
18
10
2
TICKINT
25
17
9
1
11011A–ATARM–04-Oct-10
COUNTFLAG
ENABLE
Table 10-
24
16
8
0