Linux下基於Qt串口編程測試

環境：

主機:Fedora 12

開發軟件：QT

目標板：MINI6410

實現功能：

目標板接收PC串口傳過來的信息並在終端輸出,目標板串口接收信息用SELECT機制

源代碼：

widget.h:

1. #ifndef WIDGET_H
2. #define WIDGET_H
4. #include <QWidget>
5. #include <QDebug>
6. #include <QTimer>
7. #include <unistd.h>
8. #include <sys/types.h>
9. #include <fcntl.h>
10. #include <sys/stat.h>
11. #include <stdio.h>
12. #include <sys/param.h>
13. #include <QVector>
14. #include <QByteArray>
15. #include <QQueue>
16. #include <QSemaphore>
17. #include <iostream>
18. #include <QFile>
19. #include "QThread"
20. #include <QtGui>
21. #include <QMutex>
22. #include <QtNetwork>
23. #include <QUdpSocket>
24. #include <sys/ioctl.h>
25. #include <stdlib.h>
26. #include <stdio.h>
27. #include <linux/soundcard.h>
28. #include <alsa/asoundlib.h>
29. #include <QtGui/QMainWindow>
30. #include <QtGui/QDialog>
31. #include <QtGui/QPushButton>
32. #include <QtGui/QHBoxLayout>
33. #include <QtGui/QVBoxLayout>
34. #include <QtGui/QGridLayout>
35. #include <QTextCodec>
36. #include <QtGui/QToolButton>
37. #include <qsocketnotifier.h>
38. #include <QTimer>
39. #include <QtNetwork/QUdpSocket>
40. #include <iostream>
41. #include <qmessagebox.h>
42. #include <qstringlist.h>
43. #include <QtNetwork>
44. #include <QUdpSocket>
45. #include <QSound>
46. #include <QMap>
47. #include <sys/socket.h>
48. #include <arpa/inet.h>
49. #include <linux/soundcard.h>
50. #include "sys/select.h"
51. #include "termios.h"
53. namespace Ui {
54. class Widget;
55. }
57. class Widget : public QWidget
58. {
59. Q_OBJECT
61. public:
62. explicit Widget(QWidget *parent = 0);
63. ~Widget();
65. private:
66. Ui::Widget *ui;
67. };
69. //端口信息定義
70. typedef struct _Port_Info
71. {
72. int baud_rate;
73. int port_fd;
74. char parity;
75. char stop_bit;
76. char flow_ctrl;
77. char data_bits;
78. }*Port_Info;
80. //打開串口
81. int open_port(char *port);
82. //關閉串口
83. void close_port(int fd);
84. //根據波特率獲得波特率設置參數
85. int get_baud_rate(unsigned long baud_rate);
86. //設置端口參數
87. int set_port(Port_Info p_info);
88. //通過串口發送數據,只能寫COMPRESS_BYTE長度數據,發送時加文件頭"JDH"
89. int send_data(int fd,char *data,int data_len);
91. #endif // WIDGET_H

1. #include "widget.h"
2. #include "ui_widget.h"
4. int Fd_Com;
5. #define COM "/dev/ttySAC1"
7. char buffer_com[1024 + 10];
8. char buffer_read_com[1024];
9. int send_index;
11. //打開串口
12. int open_port(char *port)
13. {
14. int fd;
15. if ((fd = open(port,O_RDWR | O_NOCTTY |O_NONBLOCK)) == -1)
16. {
17. perror("can not open com port!");
18. return -1;
19. }
20. }
22. //關閉指定串口
23. void close_port(int fd)
24. {
25. close(fd);
26. }
28. //根據波特率獲得響應的波特率設置參數
29. int get_baud_rate(unsigned long baud_rate)
30. {
31. switch (baud_rate)
32. {
33. case 2400:
34. return B2400;
35. case 4800:
36. return B4800;
37. case 9600:
38. return B9600;
39. case 19200:
40. return B19200;
41. case 38400:
42. return B38400;
43. case 57600:
44. return B57600;
45. case 115200:
46. return B115200;
47. case 230400:
48. return B230400;
49. default:
50. return -1;
51. }
52. }
54. //設置端口
55. int set_port(Port_Info p_info)
56. {
57. struct termios old_opt,new_opt;
58. int baud_rate,parity;
60. memset(&old_opt,0,sizeof(old_opt));
61. memset(&new_opt,0,sizeof(new_opt));
63. cfmakeraw(&new_opt);
64. tcgetattr(p_info->port_fd,&old_opt);
66. //設置串口波特率
67. baud_rate = get_baud_rate(p_info->baud_rate);
68. //修改new_opt結構中的串口輸入/輸出波特率槽參數
69. cfsetispeed(&new_opt,baud_rate);
70. cfsetospeed(&new_opt,baud_rate);
72. //修改控制模式，保證程序不會占用串口
73. new_opt.c_cflag |= CLOCAL;
74. //修改控制模式，使得能夠從串口讀取輸入數據
75. new_opt.c_cflag |= CREAD;
77. //設置數據流控制
78. switch (p_info->flow_ctrl)
79. {
80. case '0':
81. {
82. //不使用流控制
83. new_opt.c_cflag &= ~CRTSCTS;
84. break;
85. }
86. case '1':
87. {
88. //使用硬件進行流控制
89. new_opt.c_cflag |= CRTSCTS;
90. break;
91. }
92. case '2':
93. {
94. new_opt.c_cflag |= IXON | IXOFF | IXANY;
95. break;
96. }
97. }
99. //設置數據位
100. new_opt.c_cflag &= ~CSIZE;
101. switch (p_info->data_bits)
102. {
103. case '5':
104. {
105. new_opt.c_cflag |= CS5;
106. break;
107. }
108. case '6':
109. {
110. new_opt.c_cflag |= CS6;
111. break;
112. }
113. case '7':
114. {
115. new_opt.c_cflag |= CS7;
116. break;
117. }
118. case '8':
119. {
120. new_opt.c_cflag |= CS8;
121. break;
122. }
123. default:
124. {
125. new_opt.c_cflag |= CS8;
126. break;
127. }
128. }
130. //設置奇偶校驗位
131. switch (p_info->parity)
132. {
133. case '0':
134. {
135. //不使用奇偶校驗
136. new_opt.c_cflag &= ~PARENB;
137. break;
138. }
139. case '1':
140. {
141. //使用偶校驗
142. new_opt.c_cflag |= PARENB;
143. new_opt.c_cflag &= ~PARODD;
144. break;
145. }
146. case '2':
147. {
148. //使用奇校驗
149. new_opt.c_cflag |= PARENB;
150. new_opt.c_cflag |= PARODD;
151. break;
152. }
153. }
155. //設置停止位
156. if (p_info->stop_bit == '2')
157. {
158. new_opt.c_cflag |= CSTOPB;
159. }
160. else
161. {
162. new_opt.c_cflag &= ~CSTOPB;
163. }
165. //修改輸出模式，原始數據輸出
166. new_opt.c_oflag *= ~OPOST;
167. //修改控制字符，讀取字符最小個數為1
168. new_opt.c_cc[VMIN] = 1;
169. //修改控制字符，讀取第一個字符等待等待1 *(1/10)s
170. new_opt.c_cc[VTIME] = 1;
172. //如果發生數據溢出，接收數據，但是不再讀取
173. tcflush(p_info->port_fd,TCIFLUSH);
175. int result;
176. result = tcsetattr(p_info->port_fd,TCSANOW,&new_opt);
177. if (result == -1)
178. {
179. perror("cannot set the serial port parameters");
180. return -1;
181. }
183. tcgetattr(p_info->port_fd,&old_opt);
184. return result;
185. }
187. Widget::Widget(QWidget *parent) :
188. QWidget(parent),
189. ui(new Ui::Widget)
190. {
191. ui->setupUi(this);
193. //串口初始化
194. //打開串口
195. Fd_Com = open_port(COM);
196. //設置串口通信參數
197. struct _Port_Info info;
198. info.baud_rate = 115200;
199. info.data_bits = 8;
200. info.flow_ctrl = 0;
201. info.port_fd = Fd_Com;
202. info.stop_bit = 1;
203. info.parity = 0;
205. if (set_port(&info) == -1)
206. {
207. printf("set com para wrong!!!!!!!!!!!!!");
208. }
210. int err = 0;
211. struct timeval wait_time;
212. fd_set read_fds;
213. int len_com = 0;
215. char *data = "jdh";
216. int len = write(Fd_Com,data,3);
217. if (len != 3)
218. {
219. //如果出現溢出情況
220. qDebug() << "yi chu";
221. tcflush(Fd_Com,TCOFLUSH);
222. }
224. while (1)
225. {
226. wait_time.tv_sec = 0;
227. wait_time.tv_usec = 20000;
228. FD_ZERO(&read_fds);
229. FD_SET(Fd_Com,&read_fds);
231. //err = select(Fd_Com + 1,&read_fds,NULL,NULL,&wait_time);
232. err = select(Fd_Com + 1,&read_fds,NULL,NULL,NULL);
233. if (err < 0)
234. {
235. perror("select fail");
236. continue;
237. }
238. else
239. {
240. if (err == 0)
241. {
242. //超時返回
243. //qDebug() << "chao shi";
244. continue;
245. }
246. }
248. //讀取串口聲卡
249. //判斷聲卡是否允許讀,不允許讀退出
250. if (FD_ISSET(Fd_Com,&read_fds))
251. {
252. qDebug() << "du qu sheng ka";
253. //讀取串口緩存所有數據
254. len_com = read(Fd_Com,buffer_read_com,1024);
255. qDebug() << "read com byte = " << len_com;
257. QByteArray temp;
258. temp.append(buffer_read_com,len_com);
259. qDebug() << temp;
260. }
261. }
263. qDebug() << "end";
264. }
266. Widget::~Widget()
267. {
268. delete ui;
269. }

說明:

串口在驅動中有一個緩存區,收到的數據會存放在裡面,如果一次發送數據很多,而讀取間隔很短,則每次讀取都是整個數據包的片段.