I've been using 20.3x for several years and looking to switch to 21.11x. I noticed that for the STM32L4 in hal.lld.h the following definition exists
#define STM32_LSECLK_BYP_MIN 32768
In fact I use (quite successfully) a 1024 Hz LSE -- the output of an rv-3028 RTC which leads to a much lower power solution than any alternative. I'm wondering where this constant comes from and what the implications are.
STM32_LSECLK_BYP_MIN
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Re: STM32_LSECLK_BYP_MIN
Hi,
Those kind of numbers are taken from the datasheet, frequencies below 32k are not specified for some reason.
Giovanni
Those kind of numbers are taken from the datasheet, frequencies below 32k are not specified for some reason.
Giovanni
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Re: STM32_LSECLK_BYP_MIN
Thanks! Just as a point of reference, with an rv3028 driving the STM32L43x RTC at 1024 hz, I get standby currents under 200nA and frequency accuracy of 1ppm (at 25C, but the temperature on the back of a bird is pretty close to 39C) while being able to use the stm32 alarms and, in stop mode, the lptimer.
Geoffrey
Geoffrey
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