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stm32/system_stm32f0: Add support for using HSE and PLL as SYSCLK. 

To configure the SYSCLK on an F0 enable one of:

    MICROPY_HW_CLK_USE_HSI48
    MICROPY_HW_CLK_USE_HSE
    MICROPY_HW_CLK_USE_BYPASS
pull/1/head
Damien George 2019-04-18 15:59:47 +10:00
parent f1774fa049
commit 11657f2f20
2 changed files with 29 additions and 3 deletions
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1
ports/stm32/boards/NUCLEO_F091RC/mpconfigboard.h
View File

@ -17,6 +17,7 @@
#define MICROPY_HW_HAS_SWITCH (1)
// For system clock, board uses internal 48MHz, HSI48
#define MICROPY_HW_CLK_USE_HSI48 (1)
// The board has an external 32kHz crystal
#define MICROPY_HW_RTC_USE_LSE (1)

31
ports/stm32/system_stm32f0.c
View File

@ -40,7 +40,7 @@
******************************************************************************
*/
#include STM32_HAL_H
#include "py/mphal.h"
#ifndef HSE_VALUE
#define HSE_VALUE (8000000)
@ -135,12 +135,37 @@ void SystemClock_Config(void) {
// Set flash latency to 1 because SYSCLK > 24MHz
FLASH->ACR = (FLASH->ACR & ~0x7) | 0x1;
#if MICROPY_HW_CLK_USE_HSI48
// Use the 48MHz internal oscillator
RCC->CR2 |= RCC_CR2_HSI48ON;
while ((RCC->CR2 & RCC_CR2_HSI48RDY) == 0) {
}
RCC->CFGR |= 3 << RCC_CFGR_SW_Pos;
while (((RCC->CFGR >> RCC_CFGR_SWS_Pos) & 0x3) != 0x03) {
const uint32_t sysclk_src = 3;
#else
// Use HSE and the PLL to get a 48MHz SYSCLK
#if MICROPY_HW_CLK_USE_BYPASS
RCC->CR |= RCC_CR_HSEBYP;
#endif
RCC->CR |= RCC_CR_HSEON;
while ((RCC->CR & RCC_CR_HSERDY) == 0) {
// Wait for HSE to be ready
}
RCC->CFGR = ((48000000 / HSE_VALUE) - 2) << RCC_CFGR_PLLMUL_Pos | 2 << RCC_CFGR_PLLSRC_Pos;
RCC->CFGR2 = 0; // Input clock not divided
RCC->CR |= RCC_CR_PLLON; // Turn PLL on
while ((RCC->CR & RCC_CR_PLLRDY) == 0) {
// Wait for PLL to lock
}
const uint32_t sysclk_src = 2;
#endif
// Select SYSCLK source
RCC->CFGR |= sysclk_src << RCC_CFGR_SW_Pos;
while (((RCC->CFGR >> RCC_CFGR_SWS_Pos) & 0x3) != sysclk_src) {
// Wait for SYSCLK source to change
}