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stm32/powerctrlboot: Acquire HSEM5 on STM32WB during SystemClock_Config.

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This is required to allow using WS firmware newer than 1.1.1 concurrently
with USB (e.g. USB VCP).  It prevents CPU2 from modifying the CLK48 config
on boot.

Tested on WS=1.8 FUS=1.1.

See AN5289 and https://github.com/micropython/micropython/issues/6316
This commit is contained in:
Jim Mussared 2020-08-28 14:59:24 +10:00 committed by Damien George
parent 9c9cc7a02f
commit 0f28020a68
1 changed files with 11 additions and 0 deletions
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11
ports/stm32/powerctrlboot.c
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@ -154,12 +154,23 @@ void SystemClock_Config(void) {
#elif defined(STM32WB)
#include "stm32wbxx_ll_hsem.h"
// This semaphore protected access to the CLK48 configuration.
// CPU1 should hold this semaphore while the USB peripheral is in use.
// See AN5289 and https://github.com/micropython/micropython/issues/6316.
#define CLK48_SEMID (5)
void SystemClock_Config(void) {
// Enable the 32MHz external oscillator
RCC->CR |= RCC_CR_HSEON;
while (!(RCC->CR & RCC_CR_HSERDY)) {
}
// Prevent CPU2 from disabling CLK48.
while (LL_HSEM_1StepLock(HSEM, CLK48_SEMID)) {
}
// Use HSE and the PLL to get a 64MHz SYSCLK
#define PLLM (HSE_VALUE / 8000000) // VCO input is 8MHz
#define PLLN (24) // 24*8MHz = 192MHz