ISD94100 Series Technical Reference Manual
Sep 9, 2019
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6.3.2
Clock Generator
Five clock sources can be used to drive all the internal clocks:
32.768 kHz external low speed crystal oscillator (LXT)
4~24.576 MHz external high speed crystal oscillator (HXT)
Programmable PLL output clock frequency (PLLFOUT), PLL source can be selected
from external 4~24.576 MHz external high speed crystal (HXT) or internal high speed
oscillator (HIRC)
Selectable 48.0 MHz or 49.152 MHz internal high speed RC oscillator (HIRC)
10 kHz internal low speed RC oscillator (LIRC)
XT1_OUT
HXTEN (CLK_PWRCTL[0])
XT1_IN
Internal
48.0/49.152 MHz
Oscillator
(HIRC)
HIRCEN (CLK_PWRCTL[2])
0
1
PLL
PLLSRC (CLK_PLLCTL[19])
PLL FOUT
X32_OUT
External
32.768 kHz
Crystal
(LXT)
LXT
LXTEN (CLK_PWRCTL[1])
X32_IN
Internal
10 kHz
Oscillator
(LIRC)
LIRCEN (CLK_PWRCTL[3])
HXT
HIRC
LIRC
External
4~24.576 MHz
Crystal
(HXT)
Figure 6.3-2 Clock Generator Block Diagram
