请教马老师：串口没有输出 PC上没有显示为什么阿?
马老师，我搭了个很小的电路采集数值，想先在PC上看看数值，可是串口精灵上没有收到任何数据，郁闷，我也是第一次用串口，初始化我是用CVAVR自动生成的。即相当于用的他的应用范例。#include
#define RXB8 1
#define TXB8 0
#define UPE 2
#define OVR 3
#define FE 4
#define UDRE 5
#define RXC 7
#define FRAMING_ERROR (1<#define PARITY_ERROR (1<#define DATA_OVERRUN (1<#define DATA_REGISTER_EMPTY (1<#define RX_COMPLETE (1<
// USART0 Receiver buffer
#define RX_BUFFER_SIZE0 8
char rx_buffer0;
unsigned char rx_wr_index0,rx_rd_index0,rx_counter0;
// This flag is set on USART0 Receiver buffer overflow
bit rx_buffer_overflow0;
// USART0 Receiver interrupt service routine
#pragma savereg-
interrupt void uart0_rx_isr(void)
{
char status,data;
#asm
push r26
push r27
push r30
push r31
in r26,sreg
push r26
#endasm
status=UCSR0A;
data=UDR0;
if ((status & (FRAMING_ERROR | PARITY_ERROR | DATA_OVERRUN))==0)
{
rx_buffer0=data;
if (++rx_wr_index0 == RX_BUFFER_SIZE0) rx_wr_index0=0;
if (++rx_counter0 == RX_BUFFER_SIZE0)
{
rx_counter0=0;
rx_buffer_overflow0=1;
};
};
#asm
popr26
outsreg,r26
popr31
popr30
popr27
popr26
#endasm
}
#pragma savereg+
#ifndef _DEBUG_TERMINAL_IO_
// Get a character from the USART0 Receiver buffer
#define _ALTERNATE_GETCHAR_
#pragma used+
char getchar(void)
{
char data;
while (rx_counter0==0);
data=rx_buffer0;
if (++rx_rd_index0 == RX_BUFFER_SIZE0) rx_rd_index0=0;
#asm("cli")
--rx_counter0;
#asm("sei")
return data;
}
#pragma used-
#endif
// USART0 Transmitter buffer
#define TX_BUFFER_SIZE0 8
char tx_buffer0;
unsigned char tx_wr_index0,tx_rd_index0,tx_counter0;
// USART0 Transmitter interrupt service routine
#pragma savereg-
interrupt void uart0_tx_isr(void)
{
#asm
push r26
push r27
push r30
push r31
in r26,sreg
push r26
#edasm
if (tx_counter0)
{
--tx_counter0;
UDR0=tx_buffer0;
if (++tx_rd_index0 == TX_BUFFER_SIZE0) tx_rd_index0=0;
};
#asm
popr26
outsreg,r26
popr31
popr30
popr27
popr26
#endasm
}
#pragma savereg+
#ifndef _DEBUG_TERMINAL_IO_
// Write a character to the USART0 Transmitter buffer
#define _ALTERNATE_PUTCHAR_
#pragma used+
void putchar(char c)
{
while (tx_counter0 == TX_BUFFER_SIZE0);
#asm("cli")
if (tx_counter0 || ((UCSR0A & DATA_REGISTER_EMPTY)==0))
{
tx_buffer0=c;
if (++tx_wr_index0 == TX_BUFFER_SIZE0) tx_wr_index0=0;
++tx_counter0;
}
else
UDR0=c;
#asm("sei")
}
#pragma used-
#endif
// Standard Input/Output functions
#include
// Declare your global variables here
void main(void)
{
// USART0 initialization
// Communication Parameters: 8 Data, 1 Stop, No Parity
// USART0 Receiver: On
// USART0 Transmitter: On
// USART0 Mode: Asynchronous
// USART0 Baud rate: 9600
UCSR0A=0x00;
UCSR0B=0xD8;
UCSR0C=0x06;
UBRR0H=0x00;
UBRR0L=0x67;
// Global enable interrupts
#asm("sei")
while (1)
{
// Place your code here
};
}
以上为模板程序，我只不过加了一句话：
while (1)
{
printf ("hello world!");
};
编译是肯定没有问题的，可是PC上没有输出。。请问马老师这是为什么阿 我又加了一句 DDRD=0xFF;设置PD口为输出，还是不对. 看样子你是学软件的？不关注硬件？你必须证明你的硬件没问题，才能调试软件中的问题。 确实是硬件问题........惭愧,巨惭愧.........
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