ATmega32A串口通信奇怪问题

cloudou

• 2015-09-05

测试ATmega32A串口通信，使用内部1M振荡， 熔丝设置  通信发送ASCII码0～2，返回十六进制均为两个字节，3e 00， 4c 00， 66 00，如此简单的东西都无**常工作，令人费解。请大家帮帮忙，谢谢啦！ //ICC-AVR application builder : 2015-09-05 10:23:35 // Target : M32 // Crystal: 1.0000Mhz #include #include void USART_Transmit( unsigned char data ); void port_init(void) { PORTA = 0x00; DDRA  = 0x00; PORTB = 0x00; DDRB  = 0x00; PORTC = 0x00;  DDRC  = 0x00; PORTD = 0x00; DDRD  = 0x00; } //UART0 initialize // desired baud rate: 9600 // actual: baud rate:9615 (0.2%) void uart0_init(void) { UCSRB = 0x00; //disable while setting baud rate UCSRA = 0x02; UCSRC = BIT(URSEL) | 0x06; UBRRL = 0x0C; //set baud rate lo UBRRH = 0x00; //set baud rate hi UCSRB = 0x98; } #pragma interrupt_handler uart0_rx_isr:iv_USART0_RXC void uart0_rx_isr(void) { //uart has received a character in UDR unsigned char i=0; i=UDR; USART_Transmit(i); } //call this routine to initialize all peripherals void init_devices(void) { //stop errant interrupts until set up CLI(); //disable all interrupts port_init(); uart0_init(); MCUCR = 0x00; GICR  = 0x00; TIMSK = 0x00; //timer interrupt sources SEI(); //re-enable interrupts //all peripherals are now initialized } void USART_Transmit( unsigned char data ) { /* 等待发送缓冲器为空 */ while ( !( UCSRA & (1