Rainbow Electronics NUC140 - Manual (Page 30)

NUC140 Series DATA SHEET
5.3 Clock Controller
The clock controller generates the clock sources for the whole chip, including all AMBA interface
modules and all peripheral clocks. The clock controller also implements the power control function with
the individually clock on or off control, clock source selection and a 4-bit clock divider next to clock
source selection. The chip will into power-down mode after set the Power-Down bit and then the CPU
Cortex-M0 execute the WFI or the WFE instruction. On the power down mode, the controller turns off
the external crystal and internal oscillator to reduce the power consumption to minimum.
5.3.1 Clock Generator
The clock generator consists of 5 sources which list below:
• One external 32kHz crystal
• One external 12 MHz crystal
• One programmable PLL FOUT(PLL source consists of 12M and 22M)
• One internal 22 MHz oscillator
• One internal 10 kHz oscillator
XT_OUT
XTL12M
12M
XTL12M_EN(PWRCON[0])
XT_IN
OSC22M
22M
OSC22M_EN(PWRCON[6])
1
0
PLL
PLL_SRC(PLLCON[19])
PLL FOUT
X32O
XTL32K
32K
XTL32K_EN(PWRCON[1])
X32I
OSC10K
10K
OSC10K_EN(PWRCON[3])
12M
22M
10K
Figure 5-2 Clock generator block diagram
Publication Release Date: May 31, 2010
- 30 - Revision V1.02