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rs485_termios_test.c

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  1. #include <sys/select.h>
  2. #include <termios.h>
  3. #include <stdio.h>
  4. #include <fcntl.h>
  5. #include <unistd.h>
  6. #include <sys/time.h>
  7. #include <sys/types.h>
  8. #include <string.h>
  9. #include <stdint.h>
  10. #include <linux/serial.h>
  11. #include <sys/ioctl.h>
  12.  
  13. static const uint8_t table_crc_hi[] = {
  14.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  15.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  16.     0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  17.     0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  18.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  19.     0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
  20.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  21.     0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  22.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  23.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  24.     0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  25.     0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  26.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  27.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  28.     0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  29.     0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
  30.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  31.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  32.     0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  33.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  34.     0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,
  35.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,
  36.     0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
  37.     0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
  38.     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,
  39.     0x80, 0x41, 0x00, 0xC1, 0x81, 0x40
  40. };
  41.  
  42.  
  43. /* Table of CRC values for low-order byte */
  44. static const uint8_t table_crc_lo[] = {
  45.     0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,
  46.     0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,
  47.     0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,
  48.     0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,
  49.     0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,
  50.     0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
  51.     0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,
  52.     0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,
  53.     0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,
  54.     0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,
  55.     0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,
  56.     0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
  57.     0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,
  58.     0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,
  59.     0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,
  60.     0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,
  61.     0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,
  62.     0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
  63.     0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,
  64.     0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,
  65.     0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,
  66.     0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,
  67.     0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,
  68.     0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
  69.     0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,
  70.     0x43, 0x83, 0x41, 0x81, 0x80, 0x40
  71. };
  72.  
  73.  
  74. void calc_crc(uint8_t *buffer, ssize_t length, uint8_t *crc_hi_arg, uint8_t *crc_lo_arg) {
  75.  
  76.     uint8_t crc_hi = 0xff;
  77.     uint8_t crc_lo = 0xff;
  78.     unsigned int i;
  79.  
  80.     while (length--) {
  81.         i = crc_hi ^ *buffer++;
  82.         crc_hi = crc_lo ^ table_crc_hi[i];
  83.         crc_lo = table_crc_lo[i];
  84.     }
  85.  
  86.     *crc_hi_arg = crc_hi;
  87.     *crc_lo_arg = crc_lo;
  88.    
  89. }
  90.  
  91. int main(int argc, char **argv){
  92.  
  93.     char *dev_path = "/dev/ttyS2";
  94.     if (argc == 2) {
  95.         dev_path = argv[1];
  96.     }
  97.     uint8_t write_data[8];
  98.     int fd,write_len,select_ret, bytes_avail, status;
  99.     struct termios config;
  100.     char c;
  101.     uint8_t crc_hi, crc_lo;
  102.     fd_set activefs, tmpfs;;
  103.     struct timeval timeout;
  104.  
  105.     timeout.tv_sec = 0;
  106.     timeout.tv_usec= 500000;
  107.  
  108.     fd = open(dev_path, O_RDWR | O_NOCTTY | O_NDELAY | O_EXCL);
  109.  
  110.     if (fd == -1){
  111.         perror("open");
  112.         return 1;
  113.     }
  114.    
  115.     FD_ZERO(&tmpfs);
  116.     FD_SET(fd, &tmpfs);
  117.  
  118.     printf("opened device\n");
  119.  
  120.  
  121.     if (cfsetispeed(&config, B9600) < 0 || cfsetospeed(&config, B9600) < 0) {
  122.         printf("cant setting speed!\n");
  123.         close(fd);
  124.         return 1;
  125.     }
  126.    
  127.    
  128.     config.c_cflag |= (CREAD | CLOCAL);
  129.     config.c_cflag &=~ CSIZE;
  130.     config.c_cflag &=~ CSTOPB;
  131.     config.c_cflag &=~ PARENB;
  132.     config.c_cflag |= CS8;
  133.    
  134.     config.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
  135.    
  136.     config.c_iflag &= ~INPCK;
  137.     config.c_iflag &= ~(IXON | IXOFF| IXANY);
  138.  
  139.     config.c_oflag &= ~OPOST;
  140.    
  141.    
  142.     config.c_cc[VMIN] = 0;
  143.     config.c_cc[VTIME] = 0;
  144.  
  145.     struct serial_rs485 rs485conf;
  146.  
  147.     rs485conf.flags |= SER_RS485_ENABLED;
  148.  
  149.     /* Set logical level for RTS pin equal to 1 when sending: */
  150.     rs485conf.flags |= SER_RS485_RTS_ON_SEND;
  151.     /* or, set logical level for RTS pin equal to 0 when sending: */
  152.     //rs485conf.flags &= ~(SER_RS485_RTS_ON_SEND);
  153.  
  154.     /* Set logical level for RTS pin equal to 1 after sending: */
  155.     //rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
  156.     /* or, set logical level for RTS pin equal to 0 after sending: */
  157.     rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
  158.  
  159.     /* Set this flag if you want to receive data even whilst sending data */
  160.     rs485conf.flags |= SER_RS485_RX_DURING_TX;
  161.  
  162.     if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
  163.         perror("ioctl");
  164.         return 1;
  165.     }
  166.  
  167.     if (tcsetattr(fd, TCSANOW, &config) < 0) {
  168.         printf("cant apply config!\n");
  169.         close(fd);
  170.         return 1;
  171.     }
  172.    
  173.  
  174.     write_data[0] = 0x1f; // slave addr
  175.     write_data[1] = 0x03; // function
  176.     write_data[2] = 0x00; // data address of first coil (8b)
  177.     write_data[3] = 0x01; // data address of first coil (8b)
  178.     write_data[4] = 0x00; // num of coils requested
  179.     write_data[5] = 0x01; // num of coils requested
  180.     calc_crc(write_data, 6, &crc_hi, &crc_lo);
  181.     write_data[6] = crc_hi;
  182.     write_data[7] = crc_lo;
  183.  
  184.     printf("data: [0x%x][0x%x][0x%x][0x%x][0x%x][0x%x][0x%x][0x%x]", write_data[0], write_data[1], write_data[2], write_data[3], write_data[4], write_data[5], write_data[6], write_data[7]);
  185.  
  186.     while (1) {
  187.        
  188.         sleep(1);
  189.         write_len= write(fd, write_data, 8);
  190.         activefs = tmpfs;
  191.         select_ret = select(fd+1, &activefs, NULL, NULL, &timeout);
  192.         if (select_ret < 0) {
  193.             perror("select");
  194.             return 1;
  195.         }
  196.  
  197.         if (select_ret > 0) {
  198.             printf("select returned %d\n", select_ret);
  199.             if (read(fd, &c, 1) < 0) {
  200.                 perror("read");
  201.             } else {
  202.                 printf("received: %d\n", c);
  203.             }
  204.         }
  205.        
  206.     }
  207.  
  208.  
  209. }
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