UM10601 Datasheet, PDF (263/313 Pages) NXP Semiconductors – LPC800 User manual

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source (IRC/system oscillator) and its characteristics. The selected source can
experience more or less jitter depending on the operating conditions such as power
supply and/or ambient temperature. This is why it is suggested that when a good known
clock source is used and a PLL_NOT_LOCKED response is received, the set_pll routine
should be invoked several times before declaring the selected PLL clock source invalid.
Hint: setting Param3 equal to the system PLL frequency [Hz] divided by 10000 will
provide more than enough PLL lock-polling cycles.
22.4.2 set_power
This routine configures the device’s internal power control settings according to the calling
arguments. The goal is to reduce active power consumption while maintaining the feature
of interest to the application close to its optimum.
Remark: The set_power routine was designed for systems employing the configuration of
SYSAHBCLKDIV = 1 (System clock divider register, see Table 17 and Figure 38). Using
this routine in an application with the system clock divider not equal to 1 might not improve
microcontroller’s performance as much as in setups when the main clock and the system
clock are running at the same rate.
set_power returns a result code that reports whether the power setting was successfully
changed or not.
UM10601
Preliminary user manual
All information provided in this document is subject to legal disclaimers.
Rev. 1.0 — 7 November 2012
© NXP B.V. 2012. All rights reserved.
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