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UM10375
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 3 — 14 June 2011
297 of 368
NXP Semiconductors
UM10375
Chapter 17: LPC13xx System tick timer
17.6.4 System Timer Calibration value register (CALIB - 0xE000 E01C)
The value of the SYST_CALIB register is driven by the value of the SYSTCKCAL register
in the system configuration block (see
).
Table 287. System Timer Current value register (VAL - 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, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
Table 288. System Timer Calibration value register (CALIB - 0xE000 E01C) bit description
Bit
Symbol
Value
Description
Reset
value
23:0
TENMS
Factory preset
0x4
29:24
-
Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined.
NA
30
SKEW
Indicates whether the value of TENMS is precise. This
can affect the suitability of SysTick as a software real time
clock.
0
31
NOREF
Indicates whether a separate reference clock is available.
This value is factory preset.
0