求助ARM板中UART一直出？的问题。
各位大侠，小弟最近刚开始学习ARM，是用ADS在裸机上调。仿照学习板上的程序（基本是拷贝）编写了一个串口发送数据的程序，最后用超级终端来调试。发现没按照既定内容输出，输出几个空格之后就输出一个问号“？”(? ? ?? ? ?
?? ? ?? ? ? ? ?
?? ??? ?? ?? ?
? ? ??? ??)求解。
程序：
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include "inc\44b.h"
#include "inc\option.h"
void Delay(unsigned int);
void Uart_init(int,int);
void Uart_SendByte(int);
void Uart_Printf(char *fmt,...);
void Uart_SendString(char *pt);
void Main(void)
{
Uart_init(0,115200);
rPCONC =0xffff5555;//select all the port of GPC as output;
rPUPC = 0x0000;
while(rUMSTAT0&0x01)
{
Uart_Printf("[UART IrDA Rx Test]\n");
rPDATC =0x0000; //指示灯
Delay(10);
Uart_Printf("This test should be configured two boards.\n");
rPDATC =0x000a;//指示灯
Delay(10);
Uart_Printf("Press any key to start Rx and then Start Tx....\n");
Delay(10);
rPDATC =0x0003;//指示灯
}
}
void Delay(unsigned int x)
{
unsigned int i,j,k;
for(i=0;i<x;i++)
for(j=0;j<0xff;j++)
for(k=0;k<0xff;k++);
}
void Uart_init(int mclk,int baud)
{
int i;
if(mclk==0)
mclk=MCLK;
rUFCON0=0x0; //FIFO disable
rUFCON1=0x0;
rUMCON0=0x0;//自发自收控制
rUMCON1=0x0;
//UART0
rULCON0=0x3; //Normal,No parity,1 stop,8 bit
// rULCON0=0x7; //Normal,No parity,2 stop,8 bit
rUCON0=0x245; //rx=edge,tx=level,disable timeout int.,enable rx error int.,normal,interrupt or polling
rUBRDIV0=( (int)(mclk/16./baud + 0.5) -1 );
//UART1
// rULCON1=0x7; //Normal,No parity,2 stop,8 bit
rULCON1=0x3;
rUCON1=0x245;
rUBRDIV1=( (int)(mclk/16./baud + 0.5) -1 );
for(i=0;i<100;i++);
}
void Uart_SendByte(int data)
{
if(data=='\n')
{
while(!(rUTRSTAT0 & 0x2));
Delay(10);//because the slow response of hyper_terminal
WrUTXH0('\r');
}
while(!(rUTRSTAT0 & 0x2)); //Wait until THR is empty.
Delay(10);
WrUTXH0(data);
}
void Uart_SendString(char *pt)
{
while(*pt)
Uart_SendByte(*pt++);
}
void Uart_Printf(char *fmt,...) //可变参数宏
{
va_list ap;
char string[256];
va_start(ap,fmt);
vsprintf(string,fmt,ap);
Uart_SendString(string);
va_end(ap);
}
[解决办法]
串口连到PC机测试的？两边的波特率要设置相同，换一个“串口调试助手”试试。
[解决办法]
波特率，多试几个，比较常用的有115200,38400等
