Date: 2017-Week-39
Status: Working.

Blink the LED. When User Button is pressed, stop the LED. STM32-Blue Pill board (STM32F103C8T6)

Introduction:

Getting started with the STM32-Blue Pill generic board using the free EmBitz IDE on Windows.
To blink the LED and stop it when user button is pressed. (The button is and external added button on port B15)
Done using the Standard Peripheral Library, no HAL drivers were used.

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Information about the STM32-BluePill:

• STM32F103C8T6 microcontroller, 64KB Flash memory, 20KB SRAM in 48-pin LQFP, 4 to 16 Mhz crystal input to generate maximum 72Mhz clock
• SWD programming/Debugging interface.
• One User LED - Green _ PC13
• On-Board 8Mhz Crystal.
• On-Board 32.786Khz oscillator connected to RTC ports.
• Extension header for all QFP48 I/Os for quick connection for prototyping.

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Useful Links:

stm32duino - Blue Pill Official
Pinout Diagram
ST Microelectronics STM32 ARM MCU Site
STM32 Info @ emcu

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I did the following to get the clock working correctly at 56Mhz using the 8MHz external crystal:

system_stm32f10x.c = System Clock Configuration file.
We are using the external oscillator (HSE) which is 8Mhz
We are using PLLCLK Mux

Setup In stm32f10x.h:

1. Uncomment the line: #define USE_STDPERIPH_DRIVER
2. set this: #define HSE_VALUE ((uint32_t)8000000)
3. set this: #define HSI_VALUE ((uint32_t)8000000)

Setup In system_stm32f10x.c:

1. Uncomment the 56MHz clock config line and comment the 72MHz line as seen below:

   /* #define SYSCLK_FREQ_HSE    HSE_VALUE */
   /* #define SYSCLK_FREQ_24MHz  24000000 */
   /* #define SYSCLK_FREQ_36MHz  36000000 */
   /* #define SYSCLK_FREQ_48MHz  48000000 */
   #define SYSCLK_FREQ_56MHz  56000000
   //#define SYSCLK_FREQ_72MHz  72000000

The rest of the file will do the configuration automatically to get the following:

• PLLCLK = enabled
• PLLMul = x7
• SYSCLK = 56MHz
• AHBPrescaler = /1
• HCLK = 56Mhz
• APB1Prescaler = /2
• PCLK1 = 28Mhz
• APB2Prescaler = /1
• PCLK2 = 56Mhz

Setup In fm_stm32F1_delay.c:

1. fac_us=SystemCoreClock/8000000;