使用485主从机通信，是本人的一个测试程序，功能为自发自收。

//ICC-AVR application builder : 2008-9-6 10:26:28 // Target : M128 // Crystal: 16.000Mhz #include <iom128v.h> #include <macros.h> #include "define.h" void port_init(void) { PORTA = 0x00; DDRA = 0x00; PORTB = 0x00; DDRB = 0xff; PORTC = 0x00; //m103 output only DDRC = 0x00; PORTD = 0x00; DDRD = 0x08; PORTE = 0x00; DDRE = 0x06; PORTF = 0x00; DDRF = 0xff; PORTG = 0x00; DDRG = 0x00; } void SendAddrDelay(INT16 uiMaxDelay) { INT16 uiDelay = uiMaxDelay; while (uiDelay--); } void SendDataDelay(INT16 uiMaxDelay) { INT16 uiDelay = uiMaxDelay; while (uiDelay--); } //UART0 initialize // desired baud rate: 9600 // actual: baud rate:9615 (0.2%) // char size: 9 bit // parity: Disabled void uart0_init(void) { UCSR0B = 0x00; //disable while setting baud rate //UCSR0A = 0x01; UCSR0A = 0x00; UCSR0C = 0x06; UBRR0L = 0x67; //set baud rate lo UBRR0H = 0x00; //set baud rate hi UCSR0B = 0x9C; } //============================================================================== //串口0用于接收从机的数据 #define TX_BUFFER_LEN 100 #define RX_BUFFER_LEN 100 #define SOI 0x7e #define EOI 0x0d #define RECV_ADDR 0x01 #define RECV_DATA 0x02 volatile static UINT8 g_ucRecCommandKind = 0x00; volatile static UINT8 g_ucRecSlaveComplete = 0; volatile static UINT8 g_ucRecSlaveEnable = 0; static INT8 send_Slave[TX_BUFFER_LEN] = {0x7e,'h','e','l','l','o','3','w',0x0d}; static INT8 recv_Slave[RX_BUFFER_LEN]; volatile static UINT16 g_uiRecSlaveBegin = 0; volatile static UINT16 g_uiRecSlaveEnd = 0; //============================================================================== //volatile static UINT8 g_ucRecSlaveOk = 0; volatile static UINT8 g_ucRecSlaveAddr = 0; #pragma interrupt_handler uart0_rx_isr:19 void uart0_rx_isr(void) { //uart has received a character in UDR UINT8 ucRecData; ucRecData = UDR0; //PORTB = ~ucRecData; //接收缓冲区无新数据,且上位机已经发送从机寻址命令,等待从机回送地址 if ((g_ucRecSlaveComplete == 0) && (g_ucRecCommandKind == RECV_ADDR)) { g_ucRecSlaveAddr = ucRecData; //将接收的数据暂存 //PORTB = ucRecData; g_ucRecSlaveComplete = 1; //等待判断接收的地址与寻址的地址是否相等\ //CLI(); //while (1); //UCSR0A |= (1 << RXC0); //UCSR0B &= 0x4f; } //上位机已经向从机发送数据,等待从机回送发送的数据 if (g_ucRecCommandKind == RECV_DATA) { if(g_uiRecSlaveEnd == RX_BUFFER_LEN) //接收缓冲区满 { g_uiRecSlaveEnd = 0; } // //g_ucRecComplete g_ucRecEnable //00 数据处理完毕,允许接收新的数据 //01 正在接收新的数据 //10 接收完数据,正在处理数据 // if ((ucRecData == SOI) && (g_ucRecSlaveEnable == 0) && (g_ucRecSlaveComplete == 0)) //若接收到起始字符且允许接收标志为0 { //PORTB = ucRecData; g_uiRecSlaveEnd = 0; //清接收字符个数计数器 g_ucRecSlaveComplete = 0; //清接收完成标志 g_ucRecSlaveEnable = 1; //置允许接收标志以允许接收其它字符 //memset(recv_buffer,0,sizeof(recv_buffer)); //将接收缓冲区清空 recv_Slave[g_uiRecSlaveEnd++] = ucRecData; //保存接收的第一个字符 //PORTB = ucRecData; } else if((ucRecData == EOI) && (g_ucRecSlaveEnable == 1)) //若接收到结束字符且允许接收标志为1 { //PORTB = ucRecData; g_ucRecSlaveComplete = 1; //置接收完成标志 recv_Slave[g_uiRecSlaveEnd] = ucRecData; //保存最后一个字符 g_ucRecSlaveEnable = 0; //清允许接收标志以禁止接收其它字符 } else if (g_ucRecSlaveEnable == 1) //若允许接收其它字符 { g_ucRecSlaveComplete = 0; recv_Slave[g_uiRecSlaveEnd++] = ucRecData; //将接收的字符保存到接收缓冲区 //PORTB = ucRecData; } } } //UART1 initialize // desired baud rate:9600 // actual baud rate:9615 (0.2%) // char size: 8 bit // parity: Disabled void uart1_init(void) { UCSR1B = 0x00; //disable while setting baud rate UCSR1A = 0x00; UCSR1C = 0x06; UBRR1L = 0x67; //set baud rate lo UBRR1H = 0x00; //set baud rate hi UCSR1B = 0x98; } //============================================================================== //向上位机发送数据 void Uart1Transmit(unsigned char ucData) { while (!(UCSR1A & (1 << UDRE1))) ; UDR1 = ucData; } //============================================================================== //串口1用于接收上位机的数据 #define TX_BUFFER_LEN 100 #define RX_BUFFER_LEN 100 #define SOI 0x7e #define EOI 0x0d volatile static UINT8 g_ucRecComplete = 0; volatile static UINT8 g_ucRecEnable = 0; static INT8 send_buffer[TX_BUFFER_LEN] = {0x7e,'h','e','l','l','o','3','w',0x0d}; static INT8 recv_buffer[RX_BUFFER_LEN]; volatile static UINT16 g_uiRecBegin = 0; volatile static UINT16 g_uiRecEnd = 0; //============================================================================== #pragma interrupt_handler uart1_rx_isr:31 void uart1_rx_isr(void) { //uart has received a character in UDR UINT8 ucRecData; ucRecData = UDR1; Uart1Transmit(UDR1); if(g_uiRecEnd == RX_BUFFER_LEN) //接收缓冲区满 { g_uiRecEnd = 0; } // //g_ucRecComplete g_ucRecEnable //00 数据处理完毕,允许接收新的数据 //01 正在接收新的数据 //10 接收完数据,正在处理数据 // if ((ucRecData == SOI) && (g_ucRecEnable == 0) && (g_ucRecComplete == 0)) //若接收到起始字符且允许接收标志为0 { g_uiRecEnd = 0; //清接收字符个数计数器 g_ucRecComplete = 0; //清接收完成标志 g_ucRecEnable = 1; //置允许接收标志以允许接收其它字符 //memset(recv_buffer,0,sizeof(recv_buffer)); //将接收缓冲区清空 recv_buffer[g_uiRecEnd++] = ucRecData; //保存接收的第一个字符 } else if((ucRecData == EOI) && (g_ucRecEnable == 1)) //若接收到结束字符且允许接收标志为1 { g_ucRecComplete = 1; //置接收完成标志 recv_buffer[g_uiRecEnd] = ucRecData; //保存最后一个字符 g_ucRecEnable = 0; //清允许接收标志以禁止接收其它字符 } else if (g_ucRecEnable == 1) //若允许接收其它字符 { g_ucRecComplete = 0; recv_buffer[g_uiRecEnd++] = ucRecData; //将接收的字符保存到接收缓冲区 } } void Uart0Flush(void) { UINT8 dummy; while (UCSR0A & (1 << RXC0)) { dummy = UDR0; } } //============================================================================== //call this routine to initialize all peripherals void init_devices(void) { //stop errant interrupts until set up CLI(); //disable all interrupts XDIV = 0x00; //xtal divider XMCRA = 0x00; //external memory port_init(); uart0_init(); uart1_init(); Uart0Flush(); MCUCR = 0x00; EICRA = 0x00; //extended ext ints EICRB = 0x00; //extended ext ints EIMSK = 0x00; TIMSK = 0x00; //timer interrupt sources ETIMSK = 0x00; //extended timer interrupt sources SEI(); //re-enable interrupts //all peripherals are now initialized } //============================================================================== //向从机发送地址帧 void SendAddrFrame(unsigned char ucData) { while (!(UCSR0A & (1 << UDRE0))) ; UCSR0B |= (1 << TXB80); UDR0 = ucData;