Use TCXO for RTC clock source on STM32?

[jkrueger]

Posted on November 06, 2015 at 22:22

Has anyone used a TCXO (temperature compensated crystal oscillator powered device with driven clock output) as a clock source for the RTC on STM32F030R8T6 or STM32L152R8T6 (or any STM32) including operation in Standby mode?  Datasheet for the STM32F030R8T6 (DocID024849, rev2) p21/

55 and Reference Manual (RM0360 Rev3) p118/119/136 indicate it can be done. Similarly datasheet for the STM32L152R8T6 (DocID022799 rev11) p73 and Reference Manual (RM0038 rev13) p133/135/166 indicate it can be done.  This is an attractive alternative to using 'RTC digital calibration' for application requiring a very small RTC drift over a wide temp range.

[Amel NASRI]

Posted on November 26, 2015 at 10:25

Hi krueger.jeff,

I recommend you to have a look to the

http://www.st.com/st-web-ui/static/active/en/resource/technical/document/application_note/CD00221665.pdf

.

The section ''Guidelines for selecting suitable crystal and external components'' will help you to decide wither TCXO crystal can be used in your case or not.

This application note is also helpful to choose the compatible resonator depending on your product/crystal and application requirements.

-Mayla-