利用usb远程控制linux,Linux编程控制硬件(5) ---- 操作USB手柄

痛定思痛。 2023-01-21 08:21 157阅读 0赞

Andrew Haung 转载请注明作者及联络方式

学员项目需要用到JoyStick来远程控制云台。以前在用SDL在游戏中很简单的就可以控制。但是现在需要在Linux C下直接调用C来控制JoyStick。因此找了一些资料来看。

象如下的USB手柄基本上插入LINUX的USB口即可运行

![035887873e164cdab5c9da1d25ae03f7.png][]

20.0元

![fgetccode\_btn.gif][fgetccode_btn.gif]

Linux控制原理

Linux C控制JoyStick的比较简单，首先在JoyStick在Linux 安装好驱动后会在/dev/input生成js0.对其设备控制，就是读取相应的结构来判断用户输入哪一些指令.

当用户操作手柄时，驱动发送js\_event的结构给应用程序以通知用户作了哪一些操作。js\_event有如下定义

struct js\_event \{

unsigned int time;    /\* event timestamp in milliseconds \*/

short value; /\* value \*/

unsigned char type; /\* event type \*/

unsigned char number; /\* axis/button number \*/

\};

手柄按钮分布

![101009151725.png][]

当按下1-4号键会发送type = 1 (Button),number  = 0- 3的值

按下 select 返回 type = 1,number = 8,

按下 start 返回 type = 1,number  = 9

当按下左侧四个键.有两种情况，当按ANALOG键时(即红灯亮起)。它返回如下四个值

js\_event 的type 为2.(AXIS).

上键/下键:number  = 6，两者的区别在于value,上键按下value = -32767,松开等于 = 0.

下健按下value = 32767,松开等于 0,

左/右键:number  = 5两者的区别在于value,左键按下value = -32767,松开等于 = 0.

右健按下value = 32767,松开等于 0

当ANALOG键关闭时(即红灯灭时).

上键/下键:number  =1,    左/右键:number  =0.

下面的转动控制杆相对比较复杂。

左侧旋转杆,向上拨 type = 2,number = 1,value = -32767

向下拨  type = 2,number = 1,value = 32767

向左  type = 2,number = 2,value = -32767

向右  type = 2,number = 2,value = 32767

如果是偏于某个方向，即于返回最接近的键的值type/number，但是value有介于0到最大值之间。

当选旋转时，相当于向系统传送一系列的value渐变的jse\_event。

右侧转动控制杆是

向上type = 2,number = 2 ,value =-32767

向下拨  type = 2,number = 2,value = 32767

向左 type = 2,number = 3,value = -32767

向右  type = 2,number = 3,value = 32767

完整的控制代码

这是从网上下载的演示代码，这是调整过后正确误的

JoyStick.h

/\*

This file is part of wordwarvi.

wordwarvi is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

wordwarvi is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with wordwarvi; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

\*/

\#include

\#ifndef \_\_JOYSTICK\_H\_\_

\#define \_\_JOYSTICK\_H\_\_

\#define JOYSTICK\_DEVNAME "/dev/input/js0"

\#define JS\_EVENT\_BUTTON 0x01 /\* button pressed/released \*/

\#define JS\_EVENT\_AXIS 0x02 /\* joystick moved \*/

\#define JS\_EVENT\_INIT 0x80 /\* initial state of device \*/

struct js\_event \{

unsigned int time;    /\* event timestamp in milliseconds \*/

short value; /\* value \*/

unsigned char type; /\* event type \*/

unsigned char number; /\* axis/button number \*/

\};

struct wwvi\_js\_event \{

int button\[11\];

int stick1\_x;

int stick1\_y;

int stick2\_x;

int stick2\_y;

\};

extern int open\_joystick(char \*joystick\_device);

extern int read\_joystick\_event(struct js\_event \*jse);

extern void set\_joystick\_y\_axis(int axis);

extern void set\_joystick\_x\_axis(int axis);

extern void close\_joystick();

extern int get\_joystick\_status(struct wwvi\_js\_event \*wjse);

\#endif

JoyStick.c

\#include

\#include "joystick.h"

static int joystick\_fd = -1;

int open\_joystick(char \*joystick\_device)

joystick\_fd = open(joystick\_device, O\_RDONLY | O\_NONBLOCK); /\* read write for force feedback? \*/

if (joystick\_fd < 0)

return joystick\_fd;

/\* maybe ioctls to interrogate features here? \*/

return joystick\_fd;

int read\_joystick\_event(struct js\_event \*jse)

int bytes;

bytes = read(joystick\_fd, jse, sizeof(\*jse));

if (bytes == -1)

return 0;

if (bytes == sizeof(\*jse))

return 1;

printf("Unexpected bytes from joystick:%d\\n", bytes);

return -1;

void close\_joystick()

close(joystick\_fd);

int get\_joystick\_status(struct wwvi\_js\_event \*wjse)

int rc;

struct js\_event jse;

if (joystick\_fd < 0)

return -1;

// memset(wjse, 0, sizeof(\*wjse));

while ((rc = read\_joystick\_event(&jse) == 1)) \{

jse.type &= ~JS\_EVENT\_INIT; /\* ignore synthetic events \*/

if (jse.type == JS\_EVENT\_AXIS) \{

switch (jse.number) \{

case 0: wjse->stick1\_x = jse.value;

break;

case 1: wjse->stick1\_y = jse.value;

break;

case 2: wjse->stick2\_x = jse.value;

break;

case 3: wjse->stick2\_y = jse.value;

break;

default:

break;

\} else if (jse.type == JS\_EVENT\_BUTTON) \{

if (jse.number < 10) \{

switch (jse.value) \{

case 0:

case 1: wjse->button\[jse.number\] = jse.value;

break;

default:

break;

// printf("%d\\n", wjse->stick1\_y);

return 0;

\#if 1

/\* a little test program \*/

int main(int argc, char \*argv\[\])

int fd, rc;

int done = 0;

struct js\_event jse;

fd = open\_joystick("/dev/js0");

if (fd < 0) \{

printf("open failed.\\n");

exit(1);

while (!done) \{

rc = read\_joystick\_event(&jse);

usleep(1000);

if (rc == 1) \{

printf("Event: time %8u, value %8hd, type: %3u, axis/button: %u\\n",

jse.time, jse.value, jse.type, jse.number);

\#endif

[035887873e164cdab5c9da1d25ae03f7.png]: /images/20221020/2e48e9fa6c2647f5858831670c815f22.png
[fgetccode_btn.gif]: http://img.alimama.cn/images/tbk/cps/fgetccode_btn.gif
[101009151725.png]: http://blogimg.chinaunix.net/blog/upfile2/101009151725.png

利用usb远程控制linux,Linux编程控制硬件(5) ---- 操作USB手柄

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