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Lep
Senior
June 11, 2022
Solved

Is LSE essential in STM32WB55RGV6 BLE application?

  • June 11, 2022
  • 2 replies
  • 744 views

I make a pcb board with stm32wb55rgv6, but my LSE doesn't work and this part of the circuit was accidentally destroyed in my soldering process. Can i just use HSE or LSI in replace of LSE in BLE application? And what's the limitations?

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Best answer by Remi QUINTIN

LSE is usually used to provide the clock to the RTC. The RTC in turn gives the time base tick for the timer server that is used for all BLE timings. But note that LSE is also the clock used during low power mode.

For example, during a BLE connection, when data have been exchanged and the device is waiting for the next connection interval, it enters in STOP2 mode. But this is only achievable with the LSE clock.

You can also use HSE/1024 for the RTC but in this case you won’t be able to achieve low power mode.

2 replies

Remi QUINTIN
Remi QUINTINBest answer
ST Technical Moderator
June 21, 2022

LSE is usually used to provide the clock to the RTC. The RTC in turn gives the time base tick for the timer server that is used for all BLE timings. But note that LSE is also the clock used during low power mode.

For example, during a BLE connection, when data have been exchanged and the device is waiting for the next connection interval, it enters in STOP2 mode. But this is only achievable with the LSE clock.

You can also use HSE/1024 for the RTC but in this case you won’t be able to achieve low power mode.

Lep
LepAuthor
Senior
June 21, 2022

Thank you=) .