Bare-metal configuration for a Bluepill board.
Warning
It does not work with the Mbed Online Compiler.
Follow these steps to import and compile them with Mbed CLI:
mbed import https://os.mbed.com/users/hudakz/code/Baremetal_Blinky_Bluepill mbed compile -t GCC_ARM -m bluepill
Diff: TARGET_BLUEPILL/device/system_clock.c
- Revision:
- 0:a04710facbb6
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TARGET_BLUEPILL/device/system_clock.c Thu May 14 05:25:26 2020 +0000 @@ -0,0 +1,232 @@ +/* mbed Microcontroller Library +* Copyright (c) 2006-2017 ARM Limited +* +* Licensed under the Apache License, Version 2.0 (the "License"); +* you may not use this file except in compliance with the License. +* You may obtain a copy of the License at +* +* http://www.apache.org/licenses/LICENSE-2.0 +* +* Unless required by applicable law or agreed to in writing, software +* distributed under the License is distributed on an "AS IS" BASIS, +* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +* See the License for the specific language governing permissions and +* limitations under the License. +*/ + +/** + * This file configures the system clock as follows: + *----------------------------------------------------------------------------- + * System clock source | 1- PLL_HSE_EXTC | 3- PLL_HSI + * | (external 8 MHz clock) | (internal 8 MHz) + * | 2- PLL_HSE_XTAL | + * | (external 8 MHz xtal) | + *----------------------------------------------------------------------------- + * SYSCLK(MHz) | 72 | 64 + *----------------------------------------------------------------------------- + * AHBCLK (MHz) | 72 | 64 + *----------------------------------------------------------------------------- + * APB1CLK (MHz) | 36 | 32 + *----------------------------------------------------------------------------- + * APB2CLK (MHz) | 72 | 64 + *----------------------------------------------------------------------------- + * USB capable (48 MHz precise clock) | NO | NO + *----------------------------------------------------------------------------- + ****************************************************************************** + */ + +#include "stm32f1xx.h" + +/*!< Uncomment the following line if you need to relocate your vector Table in + Internal SRAM. */ +/* #define VECT_TAB_SRAM */ +#define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. + This value must be a multiple of 0x200. */ + + +/* Select the clock sources (other than HSI) to start with (0=OFF, 1=ON) */ +#define USE_PLL_HSE_EXTC (0) /* Use external clock */ +#define USE_PLL_HSE_XTAL (1) /* Use external xtal */ + + +#if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0) +uint8_t SetSysClock_PLL_HSE(uint8_t bypass); +#endif + +uint8_t SetSysClock_PLL_HSI(void); + + +/** + * @brief Setup the microcontroller system + * Initialize the Embedded Flash Interface, the PLL and update the + * SystemCoreClock variable. + * @note This function should be used only after reset. + * @param None + * @retval None + */ +void SystemInit (void) +{ + /* Reset the RCC clock configuration to the default reset state(for debug purpose) */ + /* Set HSION bit */ + RCC->CR |= 0x00000001U; + + /* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */ +#if !defined(STM32F105xC) && !defined(STM32F107xC) + RCC->CFGR &= 0xF8FF0000U; +#else + RCC->CFGR &= 0xF0FF0000U; +#endif /* STM32F105xC */ + + /* Reset HSEON, CSSON and PLLON bits */ + RCC->CR &= 0xFEF6FFFFU; + + /* Reset HSEBYP bit */ + RCC->CR &= 0xFFFBFFFFU; + + /* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */ + RCC->CFGR &= 0xFF80FFFFU; + +#if defined(STM32F105xC) || defined(STM32F107xC) + /* Reset PLL2ON and PLL3ON bits */ + RCC->CR &= 0xEBFFFFFFU; + + /* Disable all interrupts and clear pending bits */ + RCC->CIR = 0x00FF0000U; + + /* Reset CFGR2 register */ + RCC->CFGR2 = 0x00000000U; +#elif defined(STM32F100xB) || defined(STM32F100xE) + /* Disable all interrupts and clear pending bits */ + RCC->CIR = 0x009F0000U; + + /* Reset CFGR2 register */ + RCC->CFGR2 = 0x00000000U; +#else + /* Disable all interrupts and clear pending bits */ + RCC->CIR = 0x009F0000U; +#endif /* STM32F105xC */ + +#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG) +#ifdef DATA_IN_ExtSRAM + SystemInit_ExtMemCtl(); +#endif /* DATA_IN_ExtSRAM */ +#endif + +#ifdef VECT_TAB_SRAM + SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */ +#else + SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */ +#endif + +} + +/** + * @brief Configures the System clock source, PLL Multiplier and Divider factors, + * AHB/APBx prescalers and Flash settings + * @note This function should be called only once the RCC clock configuration + * is reset to the default reset state (done in SystemInit() function). + * @param None + * @retval None + */ +void SetSysClock(void) +{ + /* 1- Try to start with HSE and external clock */ +#if USE_PLL_HSE_EXTC != 0 + if (SetSysClock_PLL_HSE(1) == 0) +#endif + { + /* 2- If fail try to start with HSE and external xtal */ +#if USE_PLL_HSE_XTAL != 0 + if (SetSysClock_PLL_HSE(0) == 0) +#endif + { + /* 3- If fail start with HSI clock */ + if (SetSysClock_PLL_HSI() == 0) { + while(1) { + // [TODO] Put something here to tell the user that a problem occured... + } + } + } + } + + /* Output clock on MCO1 pin(PA8) for debugging purpose */ + //HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_SYSCLK, RCC_MCODIV_1); // 72 MHz or 64 MHz +} + +#if (USE_PLL_HSE_XTAL != 0) || (USE_PLL_HSE_EXTC != 0) +/******************************************************************************/ +/* PLL (clocked by HSE) used as System clock source */ +/******************************************************************************/ +uint8_t SetSysClock_PLL_HSE(uint8_t bypass) +{ + RCC_ClkInitTypeDef RCC_ClkInitStruct; + RCC_OscInitTypeDef RCC_OscInitStruct; + + /* Enable HSE oscillator and activate PLL with HSE as source */ + RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE; + if (bypass == 0) { + RCC_OscInitStruct.HSEState = RCC_HSE_ON; /* External 8 MHz xtal on OSC_IN/OSC_OUT */ + } else { + RCC_OscInitStruct.HSEState = RCC_HSE_BYPASS; /* External 8 MHz clock on OSC_IN */ + } + RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1; + RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON; + RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE; + RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9; // 72 MHz (8 MHz * 9) + if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { + return 0; // FAIL + } + + /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */ + RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2); + RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK; // 72 MHz + RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; // 72 MHz + RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2; // 36 MHz + RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1; // 72 MHz + if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { + return 0; // FAIL + } + + /* Output clock on MCO1 pin(PA8) for debugging purpose */ + //HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSE, RCC_MCODIV_1); // 8 MHz + + return 1; // OK +} +#endif + +/******************************************************************************/ +/* PLL (clocked by HSI) used as System clock source */ +/******************************************************************************/ +uint8_t SetSysClock_PLL_HSI(void) +{ + RCC_ClkInitTypeDef RCC_ClkInitStruct; + RCC_OscInitTypeDef RCC_OscInitStruct; + + /* Enable HSI oscillator and activate PLL with HSI as source */ + RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI | RCC_OSCILLATORTYPE_HSE; + RCC_OscInitStruct.HSIState = RCC_HSI_ON; + RCC_OscInitStruct.HSEState = RCC_HSE_OFF; + RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT; + RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON; + RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI_DIV2; + RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16; // 64 MHz (8 MHz/2 * 16) + if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK) { + return 0; // FAIL + } + + /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */ + RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2); + RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK; // 64 MHz + RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1; // 64 MHz + RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2; // 32 MHz + RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1; // 64 MHz + if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK) { + return 0; // FAIL + } + + /* Output clock on MCO1 pin(PA8) for debugging purpose */ + //HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_HSI, RCC_MCODIV_1); // 8 MHz + + return 1; // OK +} +