wiringSerial.c 5.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225
  1. /*
  2. * wiringSerial.c:
  3. * Handle a serial port
  4. ***********************************************************************
  5. * This file is part of wiringPi:
  6. * https://projects.drogon.net/raspberry-pi/wiringpi/
  7. *
  8. * wiringPi is free software: you can redistribute it and/or modify
  9. * it under the terms of the GNU Lesser General Public License as published by
  10. * the Free Software Foundation, either version 3 of the License, or
  11. * (at your option) any later version.
  12. *
  13. * wiringPi is distributed in the hope that it will be useful,
  14. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16. * GNU Lesser General Public License for more details.
  17. *
  18. * You should have received a copy of the GNU Lesser General Public License
  19. * along with wiringPi. If not, see <http://www.gnu.org/licenses/>.
  20. ***********************************************************************
  21. */
  22. #include <stdio.h>
  23. #include <stdlib.h>
  24. #include <stdint.h>
  25. #include <stdarg.h>
  26. #include <string.h>
  27. #include <termios.h>
  28. #include <unistd.h>
  29. #include <fcntl.h>
  30. #include <sys/ioctl.h>
  31. #include <sys/types.h>
  32. #include <sys/stat.h>
  33. #include "wiringSerial.h"
  34. /*
  35. * serialOpen:
  36. * Open and initialise the serial port, setting all the right
  37. * port parameters - or as many as are required - hopefully!
  38. *********************************************************************************
  39. */
  40. int serialOpen (const char *device, const int baud)
  41. {
  42. struct termios options ;
  43. speed_t myBaud ;
  44. int status, fd ;
  45. switch (baud)
  46. {
  47. case 50: myBaud = B50 ; break ;
  48. case 75: myBaud = B75 ; break ;
  49. case 110: myBaud = B110 ; break ;
  50. case 134: myBaud = B134 ; break ;
  51. case 150: myBaud = B150 ; break ;
  52. case 200: myBaud = B200 ; break ;
  53. case 300: myBaud = B300 ; break ;
  54. case 600: myBaud = B600 ; break ;
  55. case 1200: myBaud = B1200 ; break ;
  56. case 1800: myBaud = B1800 ; break ;
  57. case 2400: myBaud = B2400 ; break ;
  58. case 4800: myBaud = B4800 ; break ;
  59. case 9600: myBaud = B9600 ; break ;
  60. case 19200: myBaud = B19200 ; break ;
  61. case 38400: myBaud = B38400 ; break ;
  62. case 57600: myBaud = B57600 ; break ;
  63. case 115200: myBaud = B115200 ; break ;
  64. case 230400: myBaud = B230400 ; break ;
  65. case 460800: myBaud = B460800 ; break ;
  66. case 500000: myBaud = B500000 ; break ;
  67. case 576000: myBaud = B576000 ; break ;
  68. case 921600: myBaud = B921600 ; break ;
  69. case 1000000: myBaud = B1000000 ; break ;
  70. case 1152000: myBaud = B1152000 ; break ;
  71. case 1500000: myBaud = B1500000 ; break ;
  72. case 2000000: myBaud = B2000000 ; break ;
  73. case 2500000: myBaud = B2500000 ; break ;
  74. case 3000000: myBaud = B3000000 ; break ;
  75. case 3500000: myBaud = B3500000 ; break ;
  76. case 4000000: myBaud = B4000000 ; break ;
  77. default:
  78. return -2 ;
  79. }
  80. if ((fd = open (device, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK)) == -1)
  81. return -1 ;
  82. fcntl (fd, F_SETFL, O_RDWR) ;
  83. // Get and modify current options:
  84. tcgetattr (fd, &options) ;
  85. cfmakeraw (&options) ;
  86. cfsetispeed (&options, myBaud) ;
  87. cfsetospeed (&options, myBaud) ;
  88. options.c_cflag |= (CLOCAL | CREAD) ;
  89. options.c_cflag &= ~PARENB ;
  90. options.c_cflag &= ~CSTOPB ;
  91. options.c_cflag &= ~CSIZE ;
  92. options.c_cflag |= CS8 ;
  93. options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG) ;
  94. options.c_oflag &= ~OPOST ;
  95. options.c_cc [VMIN] = 0 ;
  96. options.c_cc [VTIME] = 100 ; // Ten seconds (100 deciseconds)
  97. tcsetattr (fd, TCSANOW, &options) ;
  98. ioctl (fd, TIOCMGET, &status);
  99. status |= TIOCM_DTR ;
  100. status |= TIOCM_RTS ;
  101. ioctl (fd, TIOCMSET, &status);
  102. usleep (10000) ; // 10mS
  103. return fd ;
  104. }
  105. /*
  106. * serialFlush:
  107. * Flush the serial buffers (both tx & rx)
  108. *********************************************************************************
  109. */
  110. void serialFlush (const int fd)
  111. {
  112. tcflush (fd, TCIOFLUSH) ;
  113. }
  114. /*
  115. * serialClose:
  116. * Release the serial port
  117. *********************************************************************************
  118. */
  119. void serialClose (const int fd)
  120. {
  121. close (fd) ;
  122. }
  123. /*
  124. * serialPutchar:
  125. * Send a single character to the serial port
  126. *********************************************************************************
  127. */
  128. void serialPutchar (const int fd, const unsigned char c)
  129. {
  130. write (fd, &c, 1) ;
  131. }
  132. /*
  133. * serialPuts:
  134. * Send a string to the serial port
  135. *********************************************************************************
  136. */
  137. void serialPuts (const int fd, const char *s)
  138. {
  139. write (fd, s, strlen (s)) ;
  140. }
  141. /*
  142. * serialPrintf:
  143. * Printf over Serial
  144. *********************************************************************************
  145. */
  146. void serialPrintf (const int fd, const char *message, ...)
  147. {
  148. va_list argp ;
  149. char buffer [1024] ;
  150. va_start (argp, message) ;
  151. vsnprintf (buffer, 1023, message, argp) ;
  152. va_end (argp) ;
  153. serialPuts (fd, buffer) ;
  154. }
  155. /*
  156. * serialDataAvail:
  157. * Return the number of bytes of data avalable to be read in the serial port
  158. *********************************************************************************
  159. */
  160. int serialDataAvail (const int fd)
  161. {
  162. int result ;
  163. if (ioctl (fd, FIONREAD, &result) == -1)
  164. return -1 ;
  165. return result ;
  166. }
  167. /*
  168. * serialGetchar:
  169. * Get a single character from the serial device.
  170. * Note: Zero is a valid character and this function will time-out after
  171. * 10 seconds.
  172. *********************************************************************************
  173. */
  174. int serialGetchar (const int fd)
  175. {
  176. uint8_t x ;
  177. if (read (fd, &x, 1) != 1)
  178. return -1 ;
  179. return ((int)x) & 0xFF ;
  180. }