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stm32/modmachine: Re-enable PLLSAI[1] after waking from stop mode.

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On F7s PLLSAI is used as a 48MHz clock source if the main PLL cannot
provide such a frequency, and on L4s PLLSAI1 is always used as a clock
source for the peripherals.  This commit makes sure these PLLs are
re-enabled upon waking from stop mode so the peripherals work.

See issues #4022 and #4178 (L4 specific).
This commit is contained in:
Damien George 2018-09-24 12:55:15 +10:00
parent 4df1943948
commit 1acf58c08f
1 changed files with 16 additions and 0 deletions
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16
ports/stm32/modmachine.c
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@ -568,6 +568,22 @@ STATIC mp_obj_t machine_sleep(void) {
#endif
}
#if defined(STM32F7)
if (RCC->DCKCFGR2 & RCC_DCKCFGR2_CK48MSEL) {
// Enable PLLSAI if it is selected as 48MHz source
RCC->CR |= RCC_CR_PLLSAION;
while (!(RCC->CR & RCC_CR_PLLSAIRDY)) {
}
}
#endif
#if defined(STM32L4)
// Enable PLLSAI1 for peripherals that use it
RCC->CR |= RCC_CR_PLLSAI1ON;
while (!(RCC->CR & RCC_CR_PLLSAI1RDY)) {
}
#endif
#endif
return mp_const_none;