celestronprotocol.c

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/*
 * Telescope Control Protocol for Celestron NexStar GPS telescopes
 *
 * Copyright 2003 John Kielkopf 
 * John Kielkopf (kielkopf@louisville.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
 *
 * 15 May  2003  -- Version 2.00
 *
 *
 *
 */
 
#include "celestronprotocol.h"
 
#ifndef _WIN32
#include <termios.h>
#endif
 
#define NULL_PTR(x) (x *)0
 
/* There are two classes of routines defined here:                    */
 
/*   XmTel commands to allow easy NexStar access.  These              */
/*     include routines that mimic the extensive LX200 command        */
/*     language and, for the most part, trap calls and                */
/*     respond with an error message to the console.                  */
 
/*   NexStar specific commands and data.                              */
 
/*   The NexStar command set as documented by Celestron               */
/*     is very limited.  This version of xmtel uses ta few            */
/*     auxilliary commands which permit direct access to the motor    */
/*     controllers.                                                   */
 
/* XmTel compatibility commands */
 
int ConnectTel(char *port);
void DisconnectTel(void);
int CheckConnectTel(void);
 
void SetRate(int newRate);
void SetLimits(double limitLower, double limitHigher);
double GetRA(void);
double GetDec(void);
int SlewToCoords(double newRA, double newDec);
int SyncToCoords(double newRA, double newDec);
int CheckCoords(double desRA, double desDec, double tolRA, double tolDEC);
 
void StopNSEW(void);
int SetSlewRate(void);
 
int SyncLST(double newTime);
int SyncLocalTime(void);
 
void Reticle(int reticle);
void Focus(int focus);
void Derotator(int rotate);
void Fan(int fan);
 
static int TelPortFD;
static int TelConnectFlag = 0;
 
/* NexStar local data */
 
static double returnRA;  /* Last update of RA */
static double returnDec; /* Last update of Dec */
static int updateRA;     /* Set if no RA  inquiry since last update */
static int updateDec;    /* Set if no Dec inquiry since last update */
static int slewRate;     /* Rate for slew request in StartSlew */
 
/* Coordinate reported by NexStar  = true coordinate + offset. */
 
static double offsetRA  = 0; /* Correction to RA from NexStar */
static double offsetDec = 0; /* Correction to Dec from NexStar */
 
/* NexStar local commands */
 
void GetRAandDec(void); /* Update RA and Dec from NexStar */
 
/* Serial communication utilities */
 
typedef fd_set telfds;
 
static int readn(int fd, char *ptr, int nbytes, int sec);
static int writen(int fd, char *ptr, int nbytes);
static int telstat(int fd, int sec, int usec);
 
int CheckConnectTel(void)
{
    int numRead;
    char returnStr[128];
 
    //return TelConnectFlag;
    tcflush(TelPortFD, TCIOFLUSH);
 
    /* Test connection */
 
    writen(TelPortFD, "Kx", 2);
    numRead            = readn(TelPortFD, returnStr, 3, 2);
    returnStr[numRead] = '\0';
 
    if (numRead == 2)
    {
        TelConnectFlag = 1;
        return (0);
    }
    else
        return -1;
}
 
int ConnectTel(char *port)
{
#ifdef _WIN32
    return -1;
#else
    struct termios tty;
    char returnStr[128];
    int numRead;
 
    fprintf(stderr, "Connecting to port: %s\n", port);
 
    if (TelConnectFlag != 0)
        return 0;
 
    /* Make the connection */
 
    TelPortFD = open(port, O_RDWR);
    if (TelPortFD == -1)
        return -1;
 
    tcgetattr(TelPortFD, &tty);
    cfsetospeed(&tty, (speed_t)B9600);
    cfsetispeed(&tty, (speed_t)B9600);
    tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;
    tty.c_iflag = IGNBRK;
    tty.c_lflag = 0;
    tty.c_oflag = 0;
    tty.c_cflag |= CLOCAL | CREAD;
    tty.c_cc[VMIN]  = 1;
    tty.c_cc[VTIME] = 5;
    tty.c_iflag &= ~(IXON | IXOFF | IXANY);
    tty.c_cflag &= ~(PARENB | PARODD);
    tcsetattr(TelPortFD, TCSANOW, &tty);
 
    /* Flush the input (read) buffer */
 
    tcflush(TelPortFD, TCIOFLUSH);
 
    /* Test connection */
 
    writen(TelPortFD, "Kx", 2);
    numRead            = readn(TelPortFD, returnStr, 3, 2);
    returnStr[numRead] = '\0';
 
    /* Diagnostic tests */
    fprintf(stderr, "ConnectTel read %d characters: %s\n", numRead, returnStr);
 
    if (numRead == 2)
    {
        TelConnectFlag = 1;
        return (0);
    }
    else
        return -1;
 
#endif
}
 
/* Assign and save slewRate for use in StartSlew */
 
void SetRate(int newRate)
{
    if (newRate == SLEW)
    {
        slewRate = 9;
    }
    else if (newRate == FIND)
    {
        slewRate = 6;
    }
    else if (newRate == CENTER)
    {
        slewRate = 3;
    }
    else if (newRate == GUIDE)
    {
        slewRate = 1;
    }
}
 
/* Start a slew in chosen direction at slewRate */
/* Use auxilliary NexStar command set through the hand control computer */
 
int StartSlew(int direction)
{
    char slewCmd[] = { 0x50, 0x02, 0x11, 0x24, 0x09, 0x00, 0x00, 0x00 };
    char inputStr[2048];
 
    if (direction == NORTH)
    {
        slewCmd[2] = 0x11;
        slewCmd[3] = 0x24;
        slewCmd[4] = slewRate;
    }
    else if (direction == EAST)
    {
        slewCmd[2] = 0x10;
        slewCmd[3] = 0x25;
        slewCmd[4] = slewRate;
    }
    else if (direction == SOUTH)
    {
        slewCmd[2] = 0x11;
        slewCmd[3] = 0x25;
        slewCmd[4] = slewRate;
    }
    else if (direction == WEST)
    {
        slewCmd[2] = 0x10;
        slewCmd[3] = 0x24;
        slewCmd[4] = slewRate;
    }
 
    writen(TelPortFD, slewCmd, 8);
 
    /* Look for '#' acknowledgment of request*/
 
    for (;;)
    {
        if (readn(TelPortFD, inputStr, 1, 1))
        {
            if (inputStr[0] == '#')
                return 0;
        }
        else
        {
            fprintf(stderr, "No acknowledgment from telescope in StartSlew.\n");
            return -1;
        }
    }
}
 
/* Stop the slew in chosen direction */
 
int StopSlew(int direction)
{
    char slewCmd[] = { 0x50, 0x02, 0x11, 0x24, 0x00, 0x00, 0x00, 0x00 };
    char inputStr[2048];
 
    if (direction == NORTH)
    {
        slewCmd[2] = 0x11;
        slewCmd[3] = 0x24;
    }
    else if (direction == EAST)
    {
        slewCmd[2] = 0x10;
        slewCmd[3] = 0x25;
    }
    else if (direction == SOUTH)
    {
        slewCmd[2] = 0x11;
        slewCmd[3] = 0x25;
    }
    else if (direction == WEST)
    {
        slewCmd[2] = 0x10;
        slewCmd[3] = 0x24;
    }
 
    writen(TelPortFD, slewCmd, 8);
 
    /* Look for '#' acknowledgment of request*/
 
    for (;;)
    {
        if (readn(TelPortFD, inputStr, 1, 1))
        {
            if (inputStr[0] == '#')
                return 0;
        }
        else
        {
            fprintf(stderr, "No acknowledgment from telescope in StartSlew.\n");
            return -1;
        }
    }
}
 
void DisconnectTel(void)
{
    /* printf("DisconnectTel\n"); */
    if (TelConnectFlag == 1)
        close(TelPortFD);
    TelConnectFlag = 0;
}
 
/* Test update status and return the telescope right ascension */
/* Set updateRA flag false */
/* Last telescope readout will be returned if no RA inquiry since then */
/* Otherwise force a new readout */
/* Two successive calls to GetRA will always force a new readout */
 
double GetRA(void)
{
    if (updateRA != 1)
        GetRAandDec();
    updateRA = 0;
    return returnRA;
}
 
/* Test update status and return the telescope declination */
/* Set updateDec flag false */
/* Last telescope readout will returned if no Dec inquiry since then */
/* Otherwise force a new readout */
/* Two successive calls to GetDec will always force a new readout */
 
double GetDec(void)
{
    if (updateDec != 1)
        GetRAandDec();
    updateDec = 0;
    return returnDec;
}
 
/* Read the telescope right ascension and declination and set update status */
 
int isScopeSlewing()
{
    int numRead;
    char returnStr[128];
 
    writen(TelPortFD, "L", 1);
    numRead            = readn(TelPortFD, returnStr, 2, 2);
    returnStr[numRead] = '\0';
 
    // 0 Slew complete
    // 1 Slew in progress
    return (returnStr[0] == '0' ? 0 : 1);
}
 
void GetRAandDec(void)
{
    char returnStr[12];
    int countRA, countDec;
    int numRead;
 
    writen(TelPortFD, "E", 1);
    numRead      = readn(TelPortFD, returnStr, 10, 1);
    returnStr[4] = returnStr[9] = '\0';
 
    /* Diagnostic
 *
 * printf("GetRAandDec: %d read %x\n",numRead,returnStr); 
 *
 */
 
    sscanf(returnStr, "%x", &countRA);
    sscanf(returnStr + 5, "%x:", &countDec);
    returnRA  = (double)countRA;
    returnRA  = returnRA / (3. * 15. * 60. * 65536. / 64800.);
    returnDec = (double)countDec;
    returnDec = returnDec / (3. * 60. * 65536. / 64800.);
 
    /* Account for the quadrant in declination */
 
    /* 90 to 180 */
 
    if ((returnDec > 90.) && (returnDec <= 180.))
    {
        returnDec = 180. - returnDec;
    }
 
    /* 180 to 270 */
 
    if ((returnDec > 180.) && (returnDec <= 270.))
    {
        returnDec = returnDec - 270.;
    }
 
    /* 270 to 360 */
 
    if ((returnDec > 270.) && (returnDec <= 360.))
    {
        returnDec = returnDec - 360.;
    }
 
    /* Set update flags */
 
    updateRA  = 1;
    updateDec = 1;
 
    /* Correct for offsets and return true coordinate */
    /* Coordinate reported by NexStar  = true coordinate + offset. */
 
    returnRA  = returnRA - offsetRA;
    returnDec = returnDec - offsetDec;
}
 
/* Reset telescope coordinates to new coordinates by adjusting offsets*/
/* Coordinate reported by NexStar  = true coordinate + offset. */
 
int SyncToCoords(double newRA, double newDec)
{
    /*  offsetRA = 0.;
   offsetDec = 0.;
   GetRAandDec();
   offsetRA = returnRA - newRA;
   offsetDec = returnDec - newDec;
 
   return (0);*/
 
    /* 2013-10-19 JM: Trying to support sync in Nextstar command set v4.10+ */
    char str[20];
    int n1, n2;
 
    //  so, lets format up a sync command
    n1 = newRA * 0x1000000 / 24;
    n2 = newDec * 0x1000000 / 360;
    n1 = n1 << 8;
    n2 = n2 << 8;
    sprintf((char *)str, "s%08X,%08X", n1, n2);
    writen(TelPortFD, str, 18);
 
    /* Look for '#' in response */
    for (;;)
    {
        if (readn(TelPortFD, str, 1, 2))
        {
            if (str[0] == '#')
                break;
        }
        else
            fprintf(stderr, "No acknowledgment from telescope after SyncToCoords.\n");
        return 4;
    }
    return 0;
}
 
/* 2013-11-06 JM: support location update in Nextstar command set */
int updateLocation(double lng, double lat)
{
    int lat_d, lat_m, lat_s;
    int long_d, long_m, long_s;
 
    char str[10];
    char cmd[8];
 
    // Convert from INDI standard to regular east/west -180 to 180
    if (lng > 180)
        lng -= 360;
 
    getSexComponents(lat, &lat_d, &lat_m, &lat_s);
    getSexComponents(lng, &long_d, &long_m, &long_s);
 
    cmd[0] = abs(lat_d);
    cmd[1] = lat_m;
    cmd[2] = lat_s;
    cmd[3] = lat_d > 0 ? 0 : 1;
    cmd[4] = abs(long_d);
    cmd[5] = long_m;
    cmd[6] = long_s;
    cmd[7] = long_d > 0 ? 0 : 1;
 
    sprintf((char *)str, "W%c%c%c%c%c%c%c%c", cmd[0], cmd[1], cmd[2], cmd[3], cmd[4], cmd[5], cmd[6], cmd[7]);
    writen(TelPortFD, str, 9);
 
    /* Look for '#' in response */
    for (;;)
    {
        if (readn(TelPortFD, str, 1, 2))
        {
            if (str[0] == '#')
                break;
        }
        else
            fprintf(stderr, "No acknowledgment from telescope after updateLocation.\n");
        return 4;
    }
    return 0;
}
 
int updateTime(struct ln_date *utc, double utc_offset)
{
    char str[10];
    char cmd[8];
    struct ln_zonedate local_date;
 
    // Celestron takes local time
    ln_date_to_zonedate(utc, &local_date, utc_offset * 3600);
 
    cmd[0] = local_date.hours;
    cmd[1] = local_date.minutes;
    cmd[2] = local_date.seconds;
    cmd[3] = local_date.months;
    cmd[4] = local_date.days;
    cmd[5] = local_date.years - 2000;
 
    if (utc_offset < 0)
        cmd[6] = 256 - ((unsigned int)fabs(utc_offset));
    else
        cmd[6] = ((unsigned int)fabs(utc_offset));
 
    // Always assume standard time
    cmd[7] = 0;
 
    sprintf((char *)str, "H%c%c%c%c%c%c%c%c", cmd[0], cmd[1], cmd[2], cmd[3], cmd[4], cmd[5], cmd[6], cmd[7]);
    writen(TelPortFD, str, 9);
 
    /* Look for '#' in response */
    for (;;)
    {
        if (readn(TelPortFD, str, 1, 2))
        {
            if (str[0] == '#')
                break;
        }
        else
            fprintf(stderr, "No acknowledgment from telescope after updateTime.\n");
        return 4;
    }
    return 0;
}
 
/* Slew to new coordinates */
/* Coordinate sent to NexStar  = true coordinate + offset. */
 
int SlewToCoords(double newRA, double newDec)
{
    int countRA, countDec;
    char r0, r1, r2, r3, d0, d1, d2, d3;
    double degs, hrs;
    char outputStr[32], inputStr[2048];
 
    /* Add offsets */
 
    hrs  = newRA + offsetRA;
    degs = newDec + offsetDec;
 
    /* Convert float RA to integer count */
 
    hrs     = hrs * (3. * 15. * 60. * 65536. / 64800.);
    countRA = (int)hrs;
 
    /* Account for the quadrant in declination */
 
    if ((newDec >= 0.0) && (newDec <= 90.0))
    {
        degs = degs * (3. * 60. * 65536. / 64800.);
    }
    else if ((newDec < 0.0) && (newDec >= -90.0))
    {
        degs = (360. + degs) * (3. * 60. * 65536. / 64800.);
    }
    else
    {
        fprintf(stderr, "Invalid newDec in SlewToCoords.\n");
        return 1;
    }
 
    /* Convert float Declination to integer count */
 
    countDec = (int)degs;
 
    /* Convert each integer count to four HEX characters */
    /* Inline coding just to be fast */
 
    if (countRA < 65536)
    {
        r0 = countRA % 16;
        if (r0 < 10)
        {
            r0 = r0 + 48;
        }
        else
        {
            r0 = r0 + 55;
        }
        countRA = countRA / 16;
        r1      = countRA % 16;
        if (r1 < 10)
        {
            r1 = r1 + 48;
        }
        else
        {
            r1 = r1 + 55;
        }
        countRA = countRA / 16;
        r2      = countRA % 16;
        if (r2 < 10)
        {
            r2 = r2 + 48;
        }
        else
        {
            r2 = r2 + 55;
        }
        r3 = countRA / 16;
        if (r3 < 10)
        {
            r3 = r3 + 48;
        }
        else
        {
            r3 = r3 + 55;
        }
    }
    else
    {
        printf("RA count overflow in SlewToCoords.\n");
        return 2;
    }
    if (countDec < 65536)
    {
        d0 = countDec % 16;
        if (d0 < 10)
        {
            d0 = d0 + 48;
        }
        else
        {
            d0 = d0 + 55;
        }
        countDec = countDec / 16;
        d1       = countDec % 16;
        if (d1 < 10)
        {
            d1 = d1 + 48;
        }
        else
        {
            d1 = d1 + 55;
        }
        countDec = countDec / 16;
        d2       = countDec % 16;
        if (d2 < 10)
        {
            d2 = d2 + 48;
        }
        else
        {
            d2 = d2 + 55;
        }
        d3 = countDec / 16;
        if (d3 < 10)
        {
            d3 = d3 + 48;
        }
        else
        {
            d3 = d3 + 55;
        }
    }
    else
    {
        fprintf(stderr, "Dec count overflow in SlewToCoords.\n");
        return 3;
    }
 
    /* Send the command and characters to the NexStar */
 
    sprintf(outputStr, "R%c%c%c%c,%c%c%c%c", r3, r2, r1, r0, d3, d2, d1, d0);
    writen(TelPortFD, outputStr, 10);
 
    /* Look for '#' in response */
 
    for (;;)
    {
        if (readn(TelPortFD, inputStr, 1, 2))
        {
            if (inputStr[0] == '#')
                break;
        }
        else
            fprintf(stderr, "No acknowledgment from telescope after SlewToCoords.\n");
        return 4;
    }
    return 0;
}
 
/* Test whether the destination has been reached */
/* With the NexStar we use the goto in progress query */
/* Return value is  */
/*   0 -- goto in progress */
/*   1 -- goto complete within tolerance */
/*   2 -- goto complete but outside tolerance */
 
int CheckCoords(double desRA, double desDec, double tolRA, double tolDEC)
{
    double errorRA, errorDec, nowRA, nowDec;
    char inputStr[2048];
 
    writen(TelPortFD, "L", 1);
 
    /* Look for '0#' in response indicating goto is not in progress */
 
    for (;;)
    {
        if (readn(TelPortFD, inputStr, 2, 2))
        {
            if ((inputStr[0] == '0') && (inputStr[1] == '#'))
                break;
        }
        else
            return 0;
    }
 
    nowRA    = GetRA();
    errorRA  = nowRA - desRA;
    nowDec   = GetDec();
    errorDec = nowDec - desDec;
 
    /* For 6 minute of arc precision; change as needed.  */
 
    if (fabs(errorRA) > tolRA || fabs(errorDec) > tolDEC)
        return 1;
    else
        return 2;
}
 
/* Set lower and upper limits to protect hardware */
 
void SetLimits(double limitLower, double limitHigher)
{
    limitLower = limitHigher;
    fprintf(stderr, "NexStar does not support software limits.\n");
}
 
/* Set slew speed limited by MAXSLEWRATE */
 
int SetSlewRate(void)
{
    fprintf(stderr, "NexStar does not support remote setting of slew rate.\n");
    return 0;
}
 
/* Stop all slew motion */
 
void StopNSEW(void)
{
    char inputStr[2048];
 
    writen(TelPortFD, "M", 1);
 
    /* Look for '#' */
 
    for (;;)
    {
        if (readn(TelPortFD, inputStr, 1, 1))
        {
            if (inputStr[0] == '#')
                break;
        }
        else
        {
            fprintf(stderr, "No acknowledgment from telescope in StopNSEW.\n");
        }
    }
}
 
/* Control the reticle function using predefined values */
 
void Reticle(int reticle)
{
    reticle = reticle;
    fprintf(stderr, "NexStar does not support remote setting of reticle.\n");
}
 
/* Control the focus using predefined values */
 
void Focus(int focus)
{
    focus = focus;
    fprintf(stderr, "NexStar does not support remote setting of focus.\n");
}
 
/* Control the derotator using predefined values */
 
void Derotator(int rotate)
 
{
    rotate = rotate;
    fprintf(stderr, "NexStar does not support an image derotator.\n");
}
 
/* Control the fan using predefined values */
 
void Fan(int fan)
 
{
    fan = fan;
    fprintf(stderr, "NexStar does not have a fan.\n");
}
 
/* Time synchronization utilities */
 
/* Reset the telescope sidereal time */
 
int SyncLST(double newTime)
{
    newTime = newTime;
    fprintf(stderr, "NexStar does not support remote setting of sidereal time.\n");
    return -1;
}
 
/*  Reset the telescope local time */
 
int SyncLocalTime()
{
    fprintf(stderr, "NexStar does not support remote setting of local time.\n");
    return -1;
}
 
/* Serial port utilities */
 
static int writen(fd, ptr, nbytes) int fd;
char *ptr;
int nbytes;
{
    int nleft, nwritten;
    nleft = nbytes;
    while (nleft > 0)
    {
        nwritten = write(fd, ptr, nleft);
        if (nwritten <= 0)
            break;
        nleft -= nwritten;
        ptr += nwritten;
    }
    return (nbytes - nleft);
}
 
static int readn(fd, ptr, nbytes, sec) int fd;
char *ptr;
int nbytes;
int sec;
{
    int status;
    int nleft, nread;
    nleft = nbytes;
    while (nleft > 0)
    {
        status = telstat(fd, sec, 0);
        if (status <= 0)
            break;
        nread = read(fd, ptr, nleft);
 
        /*  Diagnostic */
 
        /*    printf("readn: %d read\n", nread);  */
 
        if (nread <= 0)
            break;
        nleft -= nread;
        ptr += nread;
    }
    return (nbytes - nleft);
}
 
/*
 * Examines the read status of a file descriptor.
 * The timeout (sec, usec) specifies a maximum interval to
 * wait for data to be available in the descriptor.
 * To effect a poll, the timeout (sec, usec) should be 0.
 * Returns non-negative value on data available.
 * 0 indicates that the time limit referred by timeout expired.
 * On failure, it returns -1 and errno is set to indicate the
 * error.
 */
static int telstat(fd, sec, usec) register int fd, sec, usec;
{
    int ret;
    int width;
    struct timeval timeout;
    telfds readfds;
 
    memset((char *)&readfds, 0, sizeof(readfds));
    FD_SET(fd, &readfds);
    width           = fd + 1;
    timeout.tv_sec  = sec;
    timeout.tv_usec = usec;
    ret             = select(width, &readfds, NULL_PTR(telfds), NULL_PTR(telfds), &timeout);
    return (ret);
}