system.c

来自「MP3_PLAYER.rar」· C语言 代码 · 共 153 行

/* Includes ------------------------------------------------------------------*/
#include "config.h"

/* Global declare ------------------------------------------------------------*/
u8 Clock1s;
GPIO_InitTypeDef  GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;

/* Function declare ----------------------------------------------------------*/
int  SendChar (int ch);         
void _ttywrch (int ch) { SendChar(ch); }
void _sys_exit (int return_code) { for (;;); }
int fputc (int ch, FILE *f) { return (SendChar(ch)); }
int ferror (FILE *f) {
  /* Your implementation of ferror */
  return EOF;
} 

/*******************************************************************************
* Function Name  : SetupClock
* Description    : Configures the different system clocks.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SetupClock(void)
{

  ErrorStatus HSEStartUpStatus;
  /* RCC system reset(for debug purpose) */
  RCC_DeInit();

  /* Enable HSE */
  RCC_HSEConfig(RCC_HSE_ON);

  /* Wait till HSE is ready */
  HSEStartUpStatus = RCC_WaitForHSEStartUp();

  if(HSEStartUpStatus == SUCCESS)
  {
    /* HCLK = SYSCLK */
    RCC_HCLKConfig(RCC_SYSCLK_Div1); 
  
    /* PCLK2 = HCLK/2 */
    RCC_PCLK2Config(RCC_HCLK_Div2); 

    /* PCLK1 = HCLK/2 */
    RCC_PCLK1Config(RCC_HCLK_Div2);

	/* Flash 2 wait state */
    FLASH_SetLatency(FLASH_Latency_2);
 
   /* PLLCLK = 8MHz * 9 = 72 MHz */
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9);

    /* Enable PLL */ 
    RCC_PLLCmd(ENABLE);

    /* Wait till PLL is ready */
    while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);

    /* Select PLL as system clock source */
    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

    /* Wait till PLL is used as system clock source */
    while(RCC_GetSYSCLKSource() != 0x08);
    
  }

  /* Enable peripheral clocks --------------------------------------------------*/
  /* GPIOA, GPIOB and SPI1 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOE |
                         RCC_APB2Periph_USART1 |RCC_APB2Periph_SPI1, ENABLE);
  
  /* SysTick event each 1 ms with input clock equal to 9MHz (HCLK/8)         */
  SysTick_SetReload(9000);

  SysTick_ITConfig(ENABLE);             /* Enable SysTick interrupt           */
}

/*******************************************************************************
* Function Name  : SetupUART1
* Description    : Configures the UART1.
* Input          : None
* Output         : None
* Return         : None
*******************************************************************************/
void SetupUART1 (void)  
{
  GPIO_InitTypeDef  GPIO_InitStructure;
  USART_InitTypeDef USART_InitStructure;
  USART_ClockInitTypeDef  USART_ClockInitStructure;
  /* Enable GPIOA clock                                                       */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

  /* Configure USART1 Rx (PA10) as input floating                             */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_IN_FLOATING;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure USART1 Tx (PA9) as alternate function push-pull                */
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_9;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* USART1 configured as follow:
        - BaudRate = 115200 baud  
        - Word Length = 8 Bits
        - One Stop Bit
        - No parity
        - Hardware flow control disabled (RTS and CTS signals)
        - Receive and transmit enabled
        - USART Clock disabled
        - USART CPOL: Clock is active low
        - USART CPHA: Data is captured on the middle 
        - USART LastBit: The clock pulse of the last data bit is not output to 
                         the SCLK pin
  */
  
USART_ClockInitStructure.USART_Clock = USART_Clock_Disable;
USART_ClockInitStructure.USART_CPOL = USART_CPOL_Low;
USART_ClockInitStructure.USART_CPHA = USART_CPHA_2Edge;
USART_ClockInitStructure.USART_LastBit = USART_LastBit_Disable;
/* Configure the USART1 synchronous paramters */
USART_ClockInit(USART1, &USART_ClockInitStructure);

USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No ;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;


USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
/* Configure USART1 basic and asynchronous paramters */
USART_Init(USART1, &USART_InitStructure);

  USART_Cmd(USART1, ENABLE);           /* Enable USART1                      */
}


/* Implementation of putchar (also used by printf function to output data)    */
int SendChar (int ch)  {                /* Write character to Serial Port     */

  USART_SendData(USART1, (unsigned char) ch);
  while (!(USART1->SR & USART_FLAG_TXE));
  return (ch);
}