cancel
Showing results for 
Search instead for 
Did you mean: 

Stuck in RCC_FLAG_LSERDY after bootup when VBAT is present

devjeetmandal09
Associate

PART NO: STM32H743IIT6
CUBE_IDE VER: 1.19.0
SDK : STM32Cube FW_H7 V1.12.1

LSE PART NO. : CM9V-T1A-32.768kHz-12.5pF-20PPM-TA-QC


Hello everyone,
I am trying to use RTC on mentioned STM part number. I have enable LSE and configured the RTC.
Currently i am not using any battery, i am using a power supply with 3V to VBAT.

After boot up inside HAL_RCC_OscConfig, i am getting timeout while checking RCC_FLAG_LSERDY flag.

 
while (__HAL_RCC_GET_FLAG(RCC_FLAG_LSERDY) == 0U)
 {
    if ((HAL_GetTick() - tickstart) > RCC_LSE_TIMEOUT_VALUE)
    {
       return HAL_TIMEOUT;
    }
 }

 

The sequence is, once i have provided VDD then VBAT, everything works fine.
Next i just turn off the VDD, VBAT is still present.
Then i turn on the VDD and facing this issue.

Another thing to note is, i am not facing this issue with LSI. So i changed the crystal but facing the same issue.

Also the PDR_ON pin is connected to VDD according to specifications.

Is it possible to provide any insight of why this is happening? and how to resolve this?
Any feedback will be appreciated.

Best Regards,
Devjeet Mandal

0 REPLIES 0