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


void Delay(__IO uint32_t nCount) {
    while(nCount--) {
    }
}


void initUSART6()
{
  GPIO_InitTypeDef GPIO_InitStructure;
  USART_InitTypeDef USART_InitStruct;

  USART_StructInit(&USART_InitStruct);
  //USART_InitStruct.USART_BaudRate = 115200;
  // The following line works and produces the targeted baud rate of 115200kbps
  USART_InitStruct.USART_BaudRate = 115200 / 3;

  /* Enable GPIO clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOC, ENABLE);

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART6, ENABLE);


  /* Connect PXx to USARTx_Tx*/
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource6, GPIO_AF_USART6);

  /* Connect PXx to USARTx_Rx*/
  GPIO_PinAFConfig(GPIOC, GPIO_PinSource7, GPIO_AF_USART6);

  /* Configure USART Tx as alternate function  */
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_UP;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;

  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* Configure USART Rx as alternate function  */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
  GPIO_Init(GPIOC, &GPIO_InitStructure);

  /* USART configuration */
  USART_Init(USART6, &USART_InitStruct);

  /* Enable USART */
  USART_Cmd(USART6, ENABLE);
}


void myPrint(uint8_t *msg, uint16_t len) {
    uint16_t n;
    for (n = 0; n < len; n++) {
        while (USART_GetFlagStatus(USART6, USART_FLAG_TXE) == RESET) {}
        USART_SendData(USART6, *(msg++));
    }
}


int main(void)
{
    uint32_t cnt = 0;
    uint8_t *msg = "hello world\r\n";

    initUSART6();

    while(1) {
//      Delay(100L);
        myPrint(msg, strlen(msg));
    }

    return 0;
}