source: BAORadio/libindi/libindi/drivers/telescope/magellandriver.c @ 646

#if 0
    MAGELLAN Driver
    Copyright (C) 2011 Onno Hommes  (ohommes@alumni.cmu.edu)

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <math.h>
#include <sys/time.h>
#include <unistd.h>
#include <fcntl.h>
#include <time.h>

#include "indicom.h"
#include "indidevapi.h"
#include "magellandriver.h"

#ifndef _WIN32
#include <termios.h>
#endif

/**************************************************************************
 Connection Diagnostics
 **************************************************************************/
char ACK(int fd);
int check_magellan_connection(int fd);

/**************************************************************************
 Get Commands: store data in the supplied buffer. 
 Return 0 on success or -1 on failure 
 **************************************************************************/
 
/* Get Double from Sexagisemal */
int getCommandSexa(int fd, double *value, const char *cmd);

/* Get String */
static int getCommandString(int fd, char *data, const char* cmd);

/* Get Calender data */
int getCalenderDate(int fd, char *date);


/**************************************************************************
 Driver Implementations
 **************************************************************************/

/* 
   Check the Magellan Connection using any set command
   Magellan 1 does not support any sey but still sends
   'OK' for it
*/
int check_magellan_connection(int fd)
{
  int i=0;
 
  /* Magellan I ALways Response OK for :S?# */
  char ack[4] = ":S?#";

  char Response[64];
  int nbytes_read=0;

  #ifdef INDI_DEBUG
  IDLog("Testing telescope's connection...\n");
  #endif

  if (fd <= 0) return MAGELLAN_ERROR;

  for (i=0; i < CONNECTION_RETRIES; i++)
  {
    if (write(fd, ack, 4) < 0) return MAGELLAN_ERROR;
    
    tty_read(fd, Response, 2, MAGELLAN_TIMEOUT, &nbytes_read);
    
    if (nbytes_read == 2) return MAGELLAN_OK;
    
    usleep(50000);
  }

  tcflush(fd, TCIFLUSH);
  return MAGELLAN_ERROR;
}


/**********************************************************************
* GET FUNCTIONS
**********************************************************************/

char ACK(int fd)
{
 
  /* Magellan I ALways Response OK for :S?# (any set will do)*/
  char ack[4] = ":S?#";
  char Response[64];
  int nbytes_read=0;
  int i=0;
  int result = MAGELLAN_ERROR;

  /* Check for Comm handle */
  if (fd > 0) 
  {
    for (i=0; i < CONNECTION_RETRIES; i++)
    {
      /* Send ACK string to Magellan */
      if (write(fd, ack, 4) >= 0)
      {
        /* Read Response */
        tty_read(fd, Response, 2, MAGELLAN_TIMEOUT, &nbytes_read);
        
        /* If the two byte OK is returned we have an Ack */
        if (nbytes_read == 2) 
        {
          result = MAGELLAN_ACK;
          break; /* Force quick success return */
        }
        else usleep(50000);
      }
    }
  }

  tcflush(fd, TCIFLUSH);
  return result;
}

int getCommandSexa(int fd, double *value, const char * cmd)
{
  char temp_string[16];
  int result = MAGELLAN_ERROR;
  int nbytes_write=0, nbytes_read=0;
  
  if ( (tty_write_string(fd, cmd, &nbytes_write)) == TTY_OK)
  {
    if ((tty_read_section(fd, temp_string, '#', MAGELLAN_TIMEOUT, &nbytes_read)) == TTY_OK)
    {
      temp_string[nbytes_read - 1] = '\0';

      if (f_scansexa(temp_string, value))
      {
        #ifdef INDI_DEBUG
        IDLog("unable to process [%s]\n", temp_string);
        #endif
      }
      else
      {
        result = MAGELLAN_OK;
      }
    }
  }
  
  tcflush(fd, TCIFLUSH);
  return result;
}

static int getCommandString(int fd, char *data, const char* cmd)
{
    int nbytes_write=0, nbytes_read=0;
    int result = MAGELLAN_ERROR;
    
   if ( (tty_write_string(fd, cmd, &nbytes_write)) == TTY_OK)
   {
      if ((tty_read_section(fd, data, '#', MAGELLAN_TIMEOUT, &nbytes_read)) == TTY_OK)
      {
        data[nbytes_read - 1] = '\0';
        result = MAGELLAN_OK;
      }
   }

   tcflush(fd, TCIFLUSH);
   return result;
}


int getCalenderDate(int fd, char *date)
{

 int dd, mm, yy;
 char century[3];
 int result;

 if ( (result = getCommandString(fd, date, "#:GC#")) )
 {
    /* Magellan format is MM/DD/YY */
    if ((sscanf(date, "%d%*c%d%*c%d", &mm, &dd, &yy)) > 2)
    {
      /* Consider years 92 or more to be in the last century, anything less 
        in the 21st century.*/
      if (yy > CENTURY_THRESHOLD) strncpy(century, "19", 3);
      else strncpy(century, "20", 3);

      /* Format must be YYYY/MM/DD format */
      snprintf(date, 16, "%s%02d/%02d/%02d", century, yy, mm, dd);
    }
 }

 return result;
}