有哪位兄弟可以帮我解释一下这个代码吗

Question

#include <iostm8s103f3.h>
#include <intrinsics.h>

#define UART1_FLAG_TXE  (unsigned char)0x80  // Tx Data Register Empty flag
#define UART1_FLAG_RXNE (unsigned char)0x20  // Rx Data Register Not Empty flag

unsigned char RxBuf = '0';
unsigned char UART_RxBuffer[32];
unsigned char UART_TxBuffer[64];
int MyPWM = 0;
int Rxflag = 0;
int Tx_W_flag = 0;
int Tx_R_flag = 0;

/*SendByte*/
void uart_SendByte(unsigned char data)
{
  UART_TxBuffer[Tx_W_flag] = data;
  Tx_W_flag++;
  UART1_CR2 |= 0x80;
}

/*SendString*/
void uart_SendString(unsigned char Str[])
{
  unsigned char n = 0;
  while(Str[n])
    uart_SendByte(Str[n++]);
}

/*SendInt*/
void uart_SendInt(int x)
{
  static const char dec[] = "0123456789";
  unsigned int div_val = 10000;

  if (x < 0){
    x = - x;
    uart_SendByte('-');
  }
  while (div_val > 1 && div_val > x)
    div_val /= 10;
  do{
    uart_SendByte (dec[x / div_val]);
    x %= div_val;
    div_val /= 10;
  }while(div_val);
}

int main( void )
{
  // setup clock
  CLK_CKDIVR &= (unsigned char)(~0x18);  // 16MHz high speed internal clock
 
  // setup uart: 115200, 8-n-1
  // reference: Table 54. Baud rate programming and error calculation
  UART1_CR1 = 0x00;  // 1-8-nn, uart enabled, no parity check and interrupt
  UART1_CR2 = 0x2C;  // rx/tx enabled, rx int enabled, tx int disabled
  //UART1_CR2 = 0xAC;  // rx/tx enabled, rxne int enabled, txc int disabled
  UART1_CR3 = 0x00;  // 1 stop bits
  UART1_CR5 = 0x00;  // IrDA mode disabled
  UART1_BRR2 = 0x0B;  // 115200 baud rate. must set BRR2 first
  UART1_BRR1 = 0x08;  // 115200 baud rate. must set BRR2 first
 
    //LED: B5
  PB_DDR |= 0x20;  // output
  PB_CR1 |= 0x20;  // push pull
  PB_CR2 |= 0x20;  // 10MHz output speed
 
  // enable interrupt
  __enable_interrupt();
 
  uart_SendString("usart int\r\n");
  while (1) {
  }
}
/*发送interrupt*/
#pragma vector = UART1_T_TXE_vector
__interrupt void UART1_T_TXE_Handler(void)
{
  if(Tx_W_flag == Tx_R_flag)
    UART1_CR2 &= 0x7F;
  else
  {
   UART1_DR = UART_TxBuffer[Tx_R_flag];
   Tx_R_flag++;
   }
}

/*接收interrupt*/
#pragma vector = UART1_R_RXNE_vector
__interrupt void UART1_R_RXNE_IRQHandler(void)
{
  RxBuf = UART1_DR;
  if(RxBuf >= '0' && RxBuf <= '9' || RxBuf == '?'||RxBuf == 'd'){
    UART_RxBuffer[Rxflag] = RxBuf;
    Rxflag++;
  }
  UART1_DR = RxBuf;
  if(RxBuf == 13){
    if(UART_RxBuffer[0] == 'd'){
      if(Rxflag == 4)
        MyPWM = (UART_RxBuffer[1]-'0')*10+(UART_RxBuffer[2]-'0');
      if(Rxflag == 3)
        MyPWM = (UART_RxBuffer[1]-'0');
      if(UART_RxBuffer[Rxflag-1]=='?'){
        uart_SendString("duty cycle is ");
        uart_SendInt(MyPWM);
        Rxflag=0;
      }
    }
  }
}

Answer 1

定义了一些常量命令字，封装了常用的发送与接收方法，应该是socket通讯的封装类。