How to start the RTC in the STM32F2xx?

[BRick]

How to start the RTC (real time clock) in the STM32F2xx processor with a 25 Mhz OSC

[Imen.D]

Hello,

You can start with RTC example within STM32CubeF2 firmware package and modify this working application depending on your needs:

STM32Cube_FW_F2_V1.7.0\Projects\STM32F207ZG-Nucleo\Examples\RTC

You can also use STM32CubeMX tool, this allow you to choose the microcontroller, select the peripherals you want and map them to pins graphically. Then, build and generate your starting project with initialization C code.

Kind Regards,

Imen

[Tesla DeLorean]

You want to clock it off the 25 MHz source (ie divided down HSE), or do you plan on using a 32.768 KHz LSE crystal?

I don't think the former would permit the device going into STANDBY, etc, but it would hold good time.

Should be able divide the 25 MHz to 1 MHz or less required by the RTC, and then prescaled and divided some more.