mumuzhijia

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mumuzhijia 发布于 2016-07-22 17:03:23

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HI3520D的UART1串口收发，只能发不能收的问题

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HI3520D的UART1串口可以向外发，但是其他数据向串口发，串口的数据寄存器有值，但是这个值读取不出来，又发出去了，是不是发生了自环现象，UART1收到的数据又被发送出去了，这个怎么解决？需要改哪个寄存器配置吗

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vikeytwo

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vikeytwo 2016-11-23 18:19:51

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相同问题，求指导

chengyinbing

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chengyinbing 2017-04-06 17:02:56

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问题已解决，不是硬件问题，是参数设置问题：请参考以下代码
#include
#include
#include
#include

#define RS485_DEV                      "/dev/ttyAMA1"

CRS485::CRS485()
{
hasRs485Inited = false;
mFd = -1;
}

CRS485::~CRS485()
{
DEBUG_INFO(DEV_MNG, "RS485 exit");
if( mFd != -1 )
{
      close( mFd );
}
hasRs485Inited = false;
}

int CRS485::setRS485(int band, int stopBit, int parity, int dataBit)
{
int status = -1;

struct termios options;
tcgetattr( mFd, &options );
tcflush( mFd, TCIOFLUSH ); // discard data written to RS485 that hasn't not been transmitted
// set band rate
switch( band )
{
case 1200:
      cfsetispeed( &options, B1200 );
      cfsetospeed( &options, B1200 );
      break;
case 2400:
      cfsetispeed( &options, B2400 );
      cfsetospeed( &options, B2400 );
      break;
case 4800:
      cfsetispeed( &options, B4800 );
      cfsetospeed( &options, B4800 );
      break;
case 9600:
      cfsetispeed( &options, B9600 );
      cfsetospeed( &options, B9600 );
      break;
case 19200:
      cfsetispeed( &options, B19200 );
      cfsetospeed( &options, B19200 );
      break;
case 38400:
      cfsetispeed( &options, B38400 );
      cfsetospeed( &options, B38400 );
      break;
case 57600:
      cfsetispeed( &options, B57600 );
      cfsetospeed( &options, B57600 );
      break;
default:
      DEBUG_ERROR(DEV_MNG, "Band rate:%d is not supported, now use 9600", band);
      cfsetispeed( &options, B9600 );
      cfsetospeed( &options, B9600 );
      break;
}
status = tcsetattr( mFd, TCSANOW, &options );
if( status != 0 )
{
      DEBUG_API_ERROR( DEV_MNG, "tcsetattr(TCSANOW)");
      return -1;
}
tcflush( mFd, TCIOFLUSH );

status = tcgetattr( mFd, &options );
if( status < 0 )
{
      DEBUG_API_ERROR( DEV_MNG, "tcgetattr()");
      return -1;
}

// set data bits
options.c_cflag &= (~CSIZE);
switch( dataBit )
{
case 5:
      options.c_cflag |= CS5;
      break;
case 6:
      options.c_cflag |= CS6;
      break;
case 7:
      options.c_cflag |= CS7;
      break;
case 8:
      options.c_cflag |= CS8;
      break;
default:
      DEBUG_ERROR(DEV_MNG, "Unsupported data bits(%d)", dataBit);
      return -1;
      break;
}

// set parity
switch( parity )
{
case 0: // None
      options.c_cflag &= (~PARENB);
      options.c_iflag &= (~INPCK);
      break;
case 1: // ODD
      options.c_cflag |= (PARODD | PARENB);
      options.c_iflag |= INPCK;
      break;
case 2: // Even
      options.c_cflag |= PARENB;
      options.c_cflag &= (~PARODD);
      options.c_iflag |= INPCK;
      break;
default:
      DEBUG_ERROR(DEV_MNG, "Unsupported parity type:%d", parity);
      return -1;
      break;
}

// set stop bits
switch( stopBit )
{
case 1:
      options.c_cflag &= (~CSTOPB);
      break;
case 2:
      options.c_cflag |= CSTOPB;
      break;
default:
      DEBUG_ERROR(DEV_MNG, "Unsupported stop bits:%d", stopBit);
      return -1;
      break;
}
/* Set input parity option */
if (parity != 0)
      options.c_iflag |= INPCK;
/* Set Raw Mode */
options.c_lflag  &= ~(ICANON | ECHO | ECHOE | ISIG);  /*Input*/
options.c_oflag  &= ~OPOST; /*Output*/
tcflush( mFd, TCIFLUSH );
options.c_cc[VTIME] = 150;
options.c_cc[VMIN] = 7;

status = tcsetattr( mFd, TCSANOW, &options );
if( status != 0 )
{
      DEBUG_API_ERROR(DEV_MNG, "tcsetattr()");
      return -1;
}

return 0;
}

int CRS485::init(int band, int stopBit, int parity, int dataBit)
{
if( hasRs485Inited )
{
      DEBUG_ERROR(DEV_MNG, "RS485 has been inited");
      return -1;
}

int ret = -1;

// open device
mFd = open( RS485_DEV, O_RDWR );
if( mFd < 0 )
{
      DEBUG_API_ERROR(DEV_MNG, "open()");
      return -1;
}

ret = setRS485(band, stopBit, parity, dataBit);
if(ret == -1)
      goto ERROR;

// success
hasRs485Inited = 1;
DEBUG_INFO(DEV_MNG, "RS485 init success");
return 0;

ERROR:
close( mFd );
return -1;
}

int CRS485::sendData(char *data, int dataLen)
{
if( data == NULL )
      return -1;
if( dataLen <= 0 )
      return -1;

if( hasRs485Inited != 1 )
{
      DEBUG_ERROR(DEV_MNG, "Can't send 485 data before inited");
      return -1;
}

return write( mFd, data, dataLen );
}

int CRS485::recvData(char *data, int dataLen, int maxWaitTime)
{
if( data == NULL )
      return -1;
if( dataLen <= 0 )
      return -1;

if( hasRs485Inited != 1 )
{
      DEBUG_ERROR(DEV_MNG, "Can't recv 485 data before inited");
      return -1;
}

int index = 0;
int rc = 0;
int rcnum = dataLen;
struct timeval tv;
fd_set readfd;
tv.tv_sec = maxWaitTime / 1000;
tv.tv_usec = maxWaitTime % 1000 * 1000;
FD_ZERO(&readfd);
FD_SET(mFd, &readfd);
rc = select(mFd + 1, &readfd, NULL, NULL, &tv);
if(rc > 0)
{
      while(dataLen)
      {
         rc = read(mFd, &data[index], 1);
         if(rc > 0)
            index = index + 1;
         dataLen = dataLen - 1;
      }
      if(index != rcnum)
         return -1;
      return rcnum;
}
else
{
      return -1;
}
return -1;

//return read( mFd, data, dataLen );
}

fayfive

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fayfive 2017-04-06 20:42:15

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应该设置哪一个？我也是遇到这样的问题，值读取不出来，又发出去了，是不是发生了自环现象

yangzi8000

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yangzi8000 2017-04-07 21:03:51

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这个顶一下。。。。485

applepen

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applepen 2017-05-14 23:27:22

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本帖最后由 applepen 于 2020-3-27 22:32 编辑

options.c_cflag &=~CRTSCTS; //取消硬件流控
options.c_lflag = 0;

hero

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hero 2017-06-30 15:08:13

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好，不错，mark啦

13915426184

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13915426184 2017-09-12 10:38:08

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[quote][url=forum.php?mod=redirect&goto=findpost&pid=41763&ptid=12051]vikeytwo 发表于 2016-11-23 18:19[/url]
相同问题，求指导[/quote]

你好，请问你后来是怎么解决的？我也遇到了这个问题

testforvc

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testforvc 2017-09-28 10:30:48

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多谢分享学习了

vikeytwo

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vikeytwo 2017-10-10 07:00:18

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[quote][url=forum.php?mod=redirect&goto=findpost&pid=63864&ptid=12051]13915426184 发表于 2017-9-12 10:38[/url]
你好，请问你后来是怎么解决的？我也遇到了这个问题[/quote]

过了好久了，我也记不太清了，主要还是修改Flag