Data Sheet

NUC123

May 3, 2017 Page 48 of 99 Rev.2.04

NUC123 SERIES DATASHEET

XT1_IN

4~24 MHz

HXT

XTL12M_EN (PWRCON[0])

XT1_OUT

22.1184 MHz

HIRC

OSC22M_EN (PWRCON[2])

PLL

PLL_SRC (PLLCON[19])

PLL FOUT

10 kHz

LIRC

OSC10K_EN (PWRCON[3])

HXT

HIRC

LIRC

Legend:

HXT = 4~24 MHz external high speed crystal oscillator

HIRC = 22.1184 MHz internal high speed RC oscillator

LIRC = 10 kHz internal low speed RC oscillator

Note: Before clock switching, both the pre-selected and newly selected clock sources must be turned on

and stable.

Figure 6-9 Clock Generator Global View Diagram