MSP430 串口函数
发布时间：2008-10-22 21:56
发布者：MSP430
| #include #include void Usart0init() { char i=0; WDTCTL = WDTPW + WDTHOLD; // Stop WDT BCSCTL1 |= XTS; // ACLK = LFXT1 = HF XTAL do { IFG1 &= ~OFIFG; // Clear OSCFault flag for ( i = 0xFF; i > 0; i--); // Time for flag to set } while ((IFG1 & OFIFG) != 0); // OSCFault flag still set? BCSCTL2 |= SELM1+SELM0; // MCLK = LFXT1 (safe) UCTL0|=SWRST; //控制寄存器位 UCTL0|=CHAR; //UCTL0 = CHAR; // 8-bit character UTCTL0 = SSEL0; // UCLK = ACLK UBR00 = 0x41; // 8MHz 9600 UBR10 = 0x3; // 8MHz 9600 UMCTL0 = 0xa4; // 8MHz modulation UCTL0&=~SWRST; //选择发送时钟源置位 ME1 |= UTXE0 + URXE0; // Enable USART0 TXD/RXD IE1 |= URXIE0; // Enable USART0 RX/TX interrupt IE1 |= UTXIE0; IFG1=0X00; P3SEL |= 0x30; // P3.4,5 = USART0 TXD/RXD P3DIR |= 0x10; // P3.4 output direction _EINT(); // Enable interrupts } // USART Receiver buffer #define RX_BUFFER_SIZE 8 char rx_buffer[RX_BUFFER_SIZE]; unsigned char rx_wr_index,rx_rd_index,rx_counter; // This flag is set on USART Receiver buffer overflow char rx_buffer_overflow; // USART Receiver interrupt service routine #pragma vector=USART0RX_VECTOR __interrupt void usart0_rx (void) { char status,data; status=URCTL0; data=RXBUF0; if ((status & (FE | PE | OE))==0) { _DINT(); rx_buffer[rx_wr_index]=data; if (++rx_wr_index == RX_BUFFER_SIZE) rx_wr_index=0; if (++rx_counter == RX_BUFFER_SIZE) //如果接收缓冲区满，则置位溢出，并且清除缓冲区 { rx_counter=0; rx_buffer_overflow=1; }; _EINT(); }; } #ifndef _DEBUG_TERMINAL_IO_ // Get a character from the USART Receiver buffer #define _ALTERNATE_GETCHAR_ char getchar(void) { char data; while (rx_counter==0); data=rx_buffer[rx_rd_index]; if (++rx_rd_index == RX_BUFFER_SIZE) rx_rd_index=0; _DINT(); --rx_counter; _EINT(); return data; } #endif // USART Transmitter buffer #define TX_BUFFER_SIZE 8 char tx_buffer[TX_BUFFER_SIZE]; unsigned char tx_wr_index,tx_rd_index,tx_counter; // USART Transmitter interrupt service routine #pragma vector=USART0TX_VECTOR __interrupt void usart0_tx (void) { if (tx_counter>0) { _DINT(); --tx_counter; TXBUF0=tx_buffer[tx_rd_index]; _EINT(); if (++tx_rd_index == TX_BUFFER_SIZE) tx_rd_index=0; } } #ifndef _DEBUG_TERMINAL_IO_ // Write a character to the USART Transmitter buffer #define _ALTERNATE_PUTCHAR_ void putchar(char c)///将这个库函数定向到串口 { while (tx_counter == TX_BUFFER_SIZE); //发送缓冲区满，则等待 if (tx_counter || ((UTCTL0 & TXEPT)!=1)) { _DINT(); tx_buffer[tx_wr_index]=c; if (++tx_wr_index == TX_BUFFER_SIZE) tx_wr_index=0; ++tx_counter; _EINT(); } else { TXBUF0=c; } } #endif |
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