 |
数据搜索系统，热门电子元器件搜索 |
|
|
数据搜索系统，热门电子元器件搜索 |
|
ST7LITEUS5 数据表(PDF) 29 Page - STMicroelectronics |
|
|
|||||||||||||||||||||||||||||
ST7LITEUS5 数据表(HTML) 29 Page - STMicroelectronics |
|
|
29 / 136 page  Obsolete Product(s) - Obsolete Product(s) Obsolete Product(s) - Obsolete Product(s) ST7LITEUS2, ST7LITEUS5 Supply, reset and clock management 29/136 Note: 1 In I2C mode, the internal RC oscillator is forced as a clock source, regardless of the selection in the option byte. Refer to note 5 in Section 4.4 on page 19 for further details. 2See Section 12: Electrical characteristics for more information on the frequency and accuracy of the RC oscillator. 3 To improve clock stability and frequency accuracy, it is recommended to place a decoupling capacitor, typically 100nF, between the VDD and VSS pins as close as possible to the ST7 device. Caution: If the voltage or temperature conditions change in the application, the frequency may need to be recalibrated. Refer to application note AN2326 for information on how to calibrate the RC frequency using an external reference signal. The ST7LITEUS2 and ST7LITEUS5 also contain an Auto-wakeup RC oscillator. This RC oscillator should be enabled to enter Auto-wakeup from Halt mode. The Auto-wakeup RC oscillator can also be configured as the startup clock through the CKSEL[1:0] option bits (see Section 14.1 on page 123). This is recommended for applications where very low power consumption is required. Switching from one startup clock to another can be done in run mode as follows (see Figure 9): Case 1 Switching from internal RC to AWU: 1. Set the RC/AWU bit in the CKCNTCSR register to enable the AWU RC oscillator 2. The RC_FLAG is cleared and the clock output is at 1. 3. Wait 3 AWU RC cycles till the AWU_FLAG is set 4. The switch to the AWU clock is made at the positive edge of the AWU clock signal 5. Once the switch is made, the internal RC is stopped Case 2 Switching from AWU RC to internal RC: 1. Reset the RC/AWU bit to enable the internal RC oscillator 2. Using a 4-bit counter, wait until 8 internal RC cycles have elapsed. The counter is running on internal RC clock. 3. Wait till the AWU_FLAG is cleared (1AWU RC cycle) and the RC_FLAG is set (2 RC cycles) 4. The switch to the internal RC clock is made at the positive edge of the internal RC clock signal 5. Once the switch is made, the AWU RC is stopped Note: 1 When the internal RC is not selected, it is stopped so as to save power consumption. 2 When the internal RC is selected, the AWU RC is turned on by hardware when entering Auto-wakeup from Halt mode. 3 When the external clock is selected, the AWU RC oscillator is always on. Obsolete Product(s) - Obsolete Product(s) |
|
链接网址 |
| ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 数据表链接 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
