Working with STM32 and HM10 BLE Part 1: Environment and connection setup

#ifndef HM_10_UART_H_
#define HM_10_UART_H_

#include "stdint.h"

void hm10_uart_init(uint32_t baud,uint32_t freq);

void hm10_write_char(unsigned char ch);

void hm10_write_at_command(unsigned char * ch);

void hm10_write_string(unsigned char * ch);


#endif /* HM_10_UART_H_ */

#include <hm_10_uart.h>
#include "stm32f4xx.h"


#define AF07 0x07


static void uart_set_baudrate(USART_TypeDef *USARTx, uint32_t PeriphClk,  uint32_t BaudRate);


void hm10_uart_init(uint32_t baud,uint32_t freq)
{
	/*Enable clock access to GPIOA and USART1*/
	RCC->APB2ENR|=RCC_APB2ENR_USART1EN;
	RCC->AHB1ENR|=RCC_AHB1ENR_GPIOAEN;
	/*Configure the GPIO for UART Mode*/
	GPIOA->MODER|=GPIO_MODER_MODE9_1;
	GPIOA->MODER&=~GPIO_MODER_MODE9_0;
	GPIOA->MODER|=GPIO_MODER_MODE10_1;
	GPIOA->MODER&=~GPIO_MODER_MODE10_0;
	GPIOA->AFR[1]|=(AF07<<GPIO_AFRH_AFSEL9_Pos)|(AF07<<GPIO_AFRH_AFSEL10_Pos); //ALT7 for UART1 (PA9 and PA10)
	/*Configure UART*/
	uart_set_baudrate(USART1,freq,baud);
	USART1->CR1|=USART_CR1_TE|USART_CR1_RE;
	USART1->CR1|=USART_CR1_RXNEIE;
	NVIC_EnableIRQ(USART1_IRQn);
	USART1->CR1|=USART_CR1_UE;
}

static uint16_t compute_uart_bd(uint32_t PeriphClk, uint32_t BaudRate)
{
	return ((PeriphClk + (BaudRate/2U))/BaudRate);
}

static void uart_set_baudrate(USART_TypeDef *USARTx, uint32_t PeriphClk,  uint32_t BaudRate)
{
	USARTx->BRR =  compute_uart_bd(PeriphClk,BaudRate);
}


void hm10_write_char(unsigned char ch)
{
	/*Make sure the transmit data register is empty*/
	while(!(USART1->SR & USART_SR_TXE)){}

	/*Write to transmit data register*/
	USART1->DR  =  (ch & 0xFF);
}


void hm10_write_at_command(unsigned char * ch)
{
	while(*ch)
	{
		hc12_write_char(*ch);
		ch++;
	}
}

void hm10_write_string(unsigned char * ch)
{
	while(*ch)
	{
		hc12_write_char(*ch);
		ch++;
	}
}

#ifndef LED_H_
#define LED_H_

void led_init(void);
void led_on(void);
void led_off(void);
void led_toggle(void);


#endif /* LED_H_ */

#include "led.h"
#include "stm32f4xx.h"


void led_init(void)
{
	RCC->AHB1ENR|=RCC_AHB1ENR_GPIOAEN;
	GPIOA->MODER|=GPIO_MODER_MODE5_0;
	GPIOA->MODER&=~GPIO_MODER_MODE5_1;

}

void led_on(void)
{
	GPIOA->BSRR=GPIO_BSRR_BS5;
}

void led_off(void)
{
	GPIOA->BSRR=GPIO_BSRR_BR5;
}

void led_toggle(void)
{
	GPIOA->ODR^=GPIO_ODR_OD5;
}

#ifndef TIME_BASE_H_
#define TIME_BASE_H_

#include "stdint.h"

void Ticks_Init(uint32_t freq);
uint32_t get_Ticks();
void delay(uint32_t delay_ms);




#endif /* TIME_BASE_H_ */

#include "time_base.h"

#include "stm32f4xx.h"


volatile uint32_t current_ticks;

void Ticks_Init(uint32_t freq)
{
	/*Load the SysTick value to be the core frequency over 1000
	 *
	 * Since th core frequency is in MHz, dividing it by 1000 will get 1ms period
	 * */
	SysTick->LOAD=(freq/1000)-1;

	/*Set the source to be internal core clock*/
	SysTick->CTRL=(1<<SysTick_CTRL_CLKSOURCE_Pos);

	/*Enable The interrupt */

	SysTick->CTRL|=(1<<SysTick_CTRL_TICKINT_Pos);

	/*Enable Systick Interrupt in NIVC*/

	NVIC_EnableIRQ(SysTick_IRQn);

	/*Enable Systick*/
	SysTick->CTRL|=(1<<SysTick_CTRL_ENABLE_Pos);


}

void SysTick_Handler()
{
	/*Increment the counter*/
	current_ticks++;
}

uint32_t get_Ticks()
{
	/*Return the counter value*/
	return current_ticks;
}

/*Spin lock the CPU to force delay*/
void delay(uint32_t delay_ms)
{

	uint32_t ticks_start=get_Ticks();

	while(get_Ticks()-ticks_start<delay_ms);
}