LM3S2793 Datasheet, PDF (122/1194 Pages) Texas Instruments – Stellaris® LM3S2793 Microcontroller

Cortex-M3 Peripherals
Register 1: SysTick Control and Status Register (STCTRL), offset 0x010
Note: This register can only be accessed from privileged mode.
The SysTick STCTRL register enables the SysTick features.
SysTick Control and Status Register (STCTRL)
Base 0xE000.E000
Offset 0x010
Type R/W, reset 0x0000.0004
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
COUNT
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
CLK_SRC INTEN ENABLE
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
Bit/Field
31:17
16
15:3
2
Name
reserved
COUNT
reserved
CLK_SRC
Type
RO
RO
RO
R/W
Reset
0x000
0
0x000
1
Description
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Count Flag
Value
0
1
Description
The SysTick timer has not counted to 0 since the last time
this bit was read.
The SysTick timer has counted to 0 since the last time
this bit was read.
This bit is cleared by a read of the register or if the STCURRENT register
is written with any value.
If read by the debugger using the DAP, this bit is cleared only if the
MasterType bit in the AHB-AP Control Register is clear. Otherwise,
the COUNT bit is not changed by the debugger read. See the ARM®
Debug Interface V5 Architecture Specification for more information on
MasterType.
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
Clock Source
Value Description
0 External reference clock. (Not implemented for most Stellaris
microcontrollers.)
1 System clock
Because an external reference clock is not implemented, this bit must
be set in order for SysTick to operate.
122
January 20, 2012
Texas Instruments-Production Data