ST9 datasheet(63/146 Pages) STMICROELECTRONICS

63 / 146 page

63/146

ST9 USER GUIDE

Figure 26

. Clock Control Unit Programming

3.6.1.2 CK_AF Source

When you execute a Wait For Interrupt (WFI) instruction using the Clock Multiplier with output

clock CLOCK2/16, the power is put in Low Power mode. To reduce this power further you

have the possibility of slowing down the INTCLK frequency by using an external clock source

CK_AF. The CK_AF clock will be selected if the WFI_CKSEL bit in the CLKCTL register is set

and if CK_AF is present.

The CK_AF source can also be used in Run mode (no WFI) to reduce power consumption if

CKAF_SEL is set and CK_AF is present.

Quartz

PLL

CK_AF

1/16

1/2

DIV2

CKAF_SEL

1/N

oscillator

MX(1:0)

source

CKAF_ST

CSU_CKSEL

6/8/10/14

XT_DIV16

DX(2:0)

CLOCK2

CLOCK1

(MODER)

(CLK_FLAG)

(CLKCTL)

(PLLCONF)

(CLK_FLAG)

CK_AF

INTCLK

Peripherals

and

CPU Clock Prescaler

XTSTOP

(CLK_FLAG)

Wait for Interrupt and Low Power Modes:

LPOWFI (CLKCTL) selects Low Power operation automatically on entering WFI mode.

WFI_CKSEL (CLKCTL) selects the CK_AF clock automatically, if present, on entering WFI mode.

XTSTOP (CLK_FLAG) automatically stops the Xtal oscillator when the CK_AF clock is present and selected.

CLOCK MULTIPLIER

ST9 数据表(PDF) 63 Page - STMicroelectronics

ST9 数据表(HTML) 63 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载

链接网址

ST9 数据表(PDF) 63 Page - STMicroelectronics

ST9 数据表(HTML) 63 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表 下载

链接网址

数据表下载