NEX ROBOTICS LPC2148 Pro Manual page 35

LPC2148 DEVELOPMENT BOARD
3. Expand the PLL Setup tree to observe the default the PLL settings.
To include the PLL code in the startup file select the checkbox next to PLL setup
heading. Here MSEL setting indicates that the onboard crystal frequency (12MHz) will
be multiplied by 5. This indicates that the CPU core frequency will be 60MHz and this is
the maximum operating frequency for LPC2148 microcontroller. Care should be taken
while selecting the multiplier value to ensure that the CPU core frequency is not beyond
the maximum value. When using the PLL setup the minimum on board crystal frequency
should be at least 10 MHz.
The PLL divider selection maintains the frequency of internal current controlled
oscillator in the range of 150-320MHz. For more information please refer LPC2148 user
manual. The default setting for MSEL is 5 and for PSEL it is 2. So the core frequency
(FCLK) is 60MHz.
To change any setting just click on it and make use of the up/down arrows.
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