ISD94100 Series Technical Reference Manual
Sep 9, 2019
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6.3 Clock Controller
6.3.1
Overview
The clock controller generates clocks for the whole chip, including system clocks and all peripheral
clocks. The clock controller also implements the power control function with the individually clock
ON/OFF control, clock source selection and a clock divider. The chip will not enter Power-down
mode until CPU sets the Power-down enable bit PDEN(CLK_PWRCTL[7]) and Cortex
®
-M4 core
executes the WFI instruction. After that, chip enters Power-down mode and wait for wake-up
interrupt source triggered to leave Power-down mode. In Power-down mode, the clock controller
turns off the 4~24.576 MHz external high speed crystal (HXT) and internal high speed RC oscillator
(HIRC) to reduce the overall system power consumption. The Figure 6.3-1 shows the clock
generator and the overview of the clock source control.
