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c# - 如何设置树莓派串口波特率?

转载 作者:行者123 更新时间:2023-11-30 18:15:34 25 4
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我有以下 .NET Core 2.0 C# 代码:

using System;
using System.Runtime.InteropServices;

namespace TestSerial
{
class Program
{
[Flags]
public enum OpenFlags
{
O_RDONLY = 0,
O_WRONLY = 1,
O_RDWR = 2,

O_NONBLOCK = 4,
}

[DllImport("libc")]
public static extern int cfsetspeed(byte[] termios_data, long speed);

[DllImport("libc")]
public static extern int tcgetattr(int fd, [Out] byte[] termios_data);

[DllImport("libc")]
public static extern int tcsetattr(int fd, int optional_actions, byte[] termios_data);

[DllImport("libc")]
public static extern int open(string pathname, OpenFlags flags);


static void Main(string[] args)
{
const string serialDevice = "/dev/serial/by-id/usb-ELT_SENSOR_EK100_V1.0_SN000001-if00-port0";

int fileDescriptor = open(serialDevice, OpenFlags.O_RDONLY | OpenFlags.O_NONBLOCK);
Console.WriteLine($"Libc.open returned {fileDescriptor}");

byte[] termiosData = new byte[256];

int result = tcgetattr(fileDescriptor, termiosData);
Console.WriteLine($"Libc.tcgetattr returned {result}");

result = cfsetspeed(termiosData, 38400);
Console.WriteLine($"Libc.cfsetspeed returned {result}");

result = tcsetattr(fileDescriptor, 0, termiosData);
Console.WriteLine($"Libc.tcsetattr returned {result}");
}
}
}

程序应该将 USB 串行端口的波特率更改为 38400。但是,程序没有按预期运行。

这是运行程序的输出:

Libc.open returned 18
Libc.tcgetattr returned 0
Libc.cfsetspeed returned -1
Libc.tcsetattr returned 0

我也仔细检查了串口设置,确实没有改变:

$ sudo stty -a -F /dev/serial/by-id/usb-ELT_SENSOR_EK100_V1.0_SN000001-if00-port0
speed 9600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;
werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
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Libc.cfsetspeed 返回错误的原因可能是什么?

最佳答案

问题是 cfsetspeed 函数的速度参数声明中的数据类型(long)不正确。速度参数的数据类型应为 uint。

这是正确的代码:

using System;
using System.Runtime.InteropServices;

namespace TestSerial
{
class Program
{
[Flags]
public enum OpenFlags
{
O_RDONLY = 0,
O_WRONLY = 1,
O_RDWR = 2,

O_NONBLOCK = 4,
}

[DllImport("libc")]
public static extern int cfsetspeed(byte[] termios_data, uint speed);

[DllImport("libc")]
public static extern int tcgetattr(int fd, [Out] byte[] termios_data);

[DllImport("libc")]
public static extern int tcsetattr(int fd, int optional_actions, byte[] termios_data);

[DllImport("libc")]
public static extern int open(string pathname, OpenFlags flags);


static void Main(string[] args)
{
const string serialDevice = "/dev/serial/by-id/usb-ELT_SENSOR_EK100_V1.0_SN000001-if00-port0";

int fileDescriptor = open(serialDevice, OpenFlags.O_RDONLY | OpenFlags.O_NONBLOCK);
Console.WriteLine($"Libc.open returned {fileDescriptor}");

byte[] termiosData = new byte[256];

int result = tcgetattr(fileDescriptor, termiosData);
Console.WriteLine($"Libc.tcgetattr returned {result}");

result = cfsetspeed(termiosData, 38400);
Console.WriteLine($"Libc.cfsetspeed returned {result}");

result = tcsetattr(fileDescriptor, 0, termiosData);
Console.WriteLine($"Libc.tcsetattr returned {result}");
}
}
}

关于c# - 如何设置树莓派串口波特率?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47912133/

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