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UM10850
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User manual
Rev. 2.4 — 13 September 2016
252 of 464
NXP Semiconductors
UM10850
Chapter 19: LPC5410x CPU system tick timer (SYSTICK)
19.5.3 System Timer Current value register
The SYST_CVR register returns the current count from the System Tick counter when it is
read by software.
19.5.4 System Timer Calibration value register
The value of the SYST_CALIB register is read-only and is provided by the value of the
SYSTCKCAL register in the system configuration block (see
Table 299. System Timer Current value register (SYST_CVR - 0xE000 E018) bit description
Bit
Symbol
Description
Reset
value
23:0
CURRENT
Reading this register returns the current value of the System Tick counter. Writing any value
clears the System Tick counter and the COUNTFLAG bit in STCTRL.
0
31:24
-
Reserved. Read value is undefined, only zero should be written.
NA
Table 300. System Timer Calibration value register (SYST_CALIB - 0xE000 E01C) bit description
Bit
Symbol
Value
Description
Reset
value
23:0
TENMS
Reload value from the SYSTCKCAL register in the SYSCON block. This field is loaded
from the SYSTCKCAL register in Syscon.
0
29:24
-
Reserved. Read value is undefined, only zero should be written.
NA
30
SKEW
Indicates whether the TENMS value will generate a precise 10 millisecond time, or an
approximation. This bit is loaded from the SYSTCKCAL register in Syscon.
When 0, the value of TENMS is considered to be precise. When 1, the value of TENMS
is not considered to be precise.
0
31
NOREF
Indicates whether an external reference clock is available. This bit is loaded from the
SYSTCKCAL register in Syscon.
When 0, a separate reference clock is available. When 1, a separate reference clock is
not available.
0