' File... HAPB_SCS.BSP

' Author... Earl Foster
' Date... 11112006
' Modified... 12312007
' {$STAMP BS2p}
' {$PBASIC 2.5}

' Purpose: Obtain high altitude photos of the Earth.  HAPB_SCS stands for
' High Altitude Photographic Balloon Secondary Computer System.  This program
' works in conjunction with HAPB_PCS (HAPB_Primary Computer System) but can be a
' stand alone program.

' This program displays GPS information via a LCD screen and provide visual
' indications that the HAPB-PCS is working.  It is a very useful program when
' not connected to a PC but provides no value during flight.

' $GPGGA, POS_UTC,LAT,LAT_D,LON,LON_D,FIX,SAT,HDOP,ALT,M,GEO_ALT,M,DGPS,DRS,*CC
' POS_UTC - UTC of position. Hours, minutes and seconds. (hhmmss)
' LAT - Latitude (ddmm.ffff)
' LAT_D - Latitude direction. (N = North, S = South)
' LON - Longitude (dddmm.ffff)
' LON_D - Longitude direction (E = East, W = West)
' FIX - GPS quality indication, 0 = fix not available, 1 = Non-differential,
'                               2 = Differential, 6 = Estimated
' SAT - Number of Satellites in use, 00 to 12

' --- HDOP, ALT, GEO_ALT are variable length
' HDOP - Horizontal diluation of precision, 0.5 to 99.9
' ALT - Antenna height above'below mean sea level, -9999.9 to 99999.9 meters
' M - constant
' GEO_ALT - Geoidal height, -999.9 to 9999.9 meters
' M - constant
' DGPS - Differential GPS data age, null if FIX <> 2
' DRS - Differential Reference Station ID, null if FIX <> 2
' *CC - Checksum


#SELECT $STAMP
  #CASE BS2, BS2E, BS2PE
    T1200       CON     813
    T2400       CON     396
    T4800       CON     188
    T9600       CON     84
    T19K2       CON     32
    TMidi       CON     12
    T38K4       CON     6
  #CASE BS2SX, BS2P
    T1200       CON     2063
    T2400       CON     1021
    T4800       CON     500
    T9600       CON     240
    T19K2       CON     110
    TMidi       CON     60
    T38K4       CON     45
  #CASE BS2PX
    T1200       CON     3313
    T2400       CON     1646
    T4800       CON     813
    T9600       CON     396
    T19K2       CON     188
    TMidi       CON     108
    T38K4       CON     84
#ENDSELECT

PFCAI           PIN     14                      ' Primary Flight Computer Active Indicator
SatAcquired     PIN     7                       ' Satellite Acquired Indicator
LT0             PIN     0                       ' External Lights
LT1             PIN     1
LT2             PIN     2
LT3             PIN     3
LT4             PIN     4


' --- LCD Contants
TxPin           CON     6
PauseShort      CON     300                     ' animation pauses
PauseLong       CON     600

' --- GPS Contants
GPSpin          CON     8                       ' GPS serial input
N4800           CON     16884                   ' GPS baud rate
CST             CON     6                       ' UTC Central time correction
DegSym          CON     176                     ' degrees symbol for report
MinSym          CON     39                      ' minutes symbol

' --- GPS Variables
UTC_HR          VAR     Byte                    ' Universal hour field
UTC_MN          VAR     Byte                    ' Universal minutes field
UTC_SC          VAR     Byte                    ' Universal seconds field
Degrees         VAR     Byte                    ' Navigation Degrees
Minutes         VAR     Byte                    ' Navigation Minutes
DMinutes        VAR     Word                    ' Navigation Decimal Minutes
Altitude        VAR     Word                    ' Sea level Height
idx             VAR     Byte                    ' Index into GPS data in SPRAM
Work            VAR     Word                    ' Scrap data and numeric conversions
fldWidth        VAR     Nib                     ' Width of field
char            VAR     Byte                    ' General purpose byte size variable

' ---Secondary Computer Start
HIGH PFCAI
' --- Initialization LCD
GOSUB LCDSetup
GOSUB LCD_Splash_Screen

ProgramSetup:
  GOSUB Seeking_Satellites
  SEROUT TxPin, T19K2, [$0c]                 ' Clear LCD
  PAUSE 5

' ---- Main Program
Main:
  SERIN GPSpin, N4800, 4000, No_GPS, [WAIT("GPGGA,"), SPSTR 82] ' Setup link to GPS and process
' Showing captured data will be replaced with storing captured data procedure

  GOSUB Parse_GPS_Altitude
  GOSUB Show_Headers
  SEROUT TxPin, T19K2, [$8A, DEC5 Altitude */ $0348, " Feet"]
  GOSUB Parse_GPS_Time
  SELECT UTC_HR
     CASE >= 12
        UTC_HR = UTC_HR - CST
     CASE ELSE
        UTC_HR = UTC_HR + CST
  ENDSELECT
  SEROUT TxPin, T19K2, [$9E, DEC2 UTC_HR, ":", DEC2 UTC_MN, ":", DEC2 UTC_SC]
  GOSUB Parse_GPS_Lat
  ' Show Latitude coordinates in degrees and decimal minutes
  SEROUT TxPin, T19K2, [$AF, DEC2 Degrees, " ", DEC2 Minutes,".", DEC4 DMinutes, MinSym, " N"]
  GOSUB Parse_GPS_Long
  ' Show Longitude coordinates in degrees and decimal minutes
  SEROUT TxPin, T19K2, [$C2, DEC3 Degrees, " ", DEC2 Minutes, ".", DEC4 DMinutes, MinSym, " W"]
'  GOSUB DigitalVideo
  GOTO Main    ' Start over again
END

' ---- Subroutines

LCDSetup:
  HIGH TxPin                      ' Set pin high to be a serial port
  PAUSE 100                       ' Pause for Serial LCD to initialize
  ' Define custom characters
  ' $00 = Ballon
  SEROUT TxPin, T19K2, [$F8,$04,$0E,$1F,$1F,$1F,$0E,$0E,$04]
  ' $01 = Payload
  SEROUT TxPin, T19K2, [$F9,$04,$04,$0E,$04,$1F,$1F,$00,$00]
  ' $02 1st Earth Panel
  SEROUT TxPin, T19K2, [$FA,$00,$00,$00,$00,$01,$03,$07,$09]
  ' $03 2nd Earth Panel
  SEROUT TxPin, T19K2, [$FB,$00,$03,$07,$0F,$1F,$1F,$09,$08]
  ' $04 3rd Earth Panel
  SEROUT TxPin, T19K2, [$FC,$0F,$18,$10,$10,$10,$00,$00,$10]
  ' $05 4th Earth Panel
  SEROUT TxPin, T19K2, [$FD,$1C,$03,$03,$00,$00,$01,$03,$07]
  ' $06 5th Earth Panel
  SEROUT TxPin, T19K2, [$FE,$00,$18,$06,$01,$00,$10,$1C,$1E]
  ' $07 6th Earth Panel
  SEROUT TxPin, T19K2, [$FF,$00,$00,$00,$00,$10,$18,$04,$0E]
  SEROUT TxPin, T19K2, [$16,$0C]
  PAUSE 5
RETURN

LCD_Splash_Screen:
    PAUSE 20
    ' Show the earth rise
    SEROUT TxPin, T19K2, [$11]
    PAUSE PauseShort
    SEROUT TxPin, T19K2, [$BC, $02, $03, $04, $05, $06, $07]   ' Step 1
    PAUSE PauseLong
    ' Ballon and payload come out
    SEROUT TxPin, T19K2, [$BD, $00]  ' Balloon drifts into screen   Step 2
    PAUSE PauseShort
    SEROUT TxPin, T19K2, [$BD, " "]  ' Clear cell                   Step 3
    SEROUT TxPin, T19K2, [$BE, $00]  ' Moves over one cell
    SEROUT TxPin, T19K2, [$BD, $03]  ' Put 2nd earth back
    PAUSE PauseShort
    SEROUT TxPin, T19K2, [$BE, " "]  ' Clear cell                   Step 4
    SEROUT TxPin, T19K2, [$BF, " "]  ' Clear cell
    SEROUT TxPin, T19K2, [$AB, $00]  ' Moves over another cell
    SEROUT TxPin, T19K2, [$BE, $04]  ' Put 3rd earth back
    SEROUT TxPin, T19K2, [$BF, $01]  ' Show payload
    PAUSE PauseShort
    SEROUT TxPin, T19K2, [$AB, " "]  ' Clear cell                   Step 5
    SEROUT TxPin, T19K2, [$BF, " "]  ' Clear cell
    SEROUT TxPin, T19K2, [$BF, $05]  ' Put 4th earth back
    SEROUT TxPin, T19K2, [$98, $00]  ' Moves up one cell
    SEROUT TxPin, T19K2, [$AC, $01]  ' Show payload
    PAUSE PAUSEShort
    SEROUT TxPin, T19K2, [$98, " "]  ' Clear cell                   Step 6
    SEROUT TxPin, T19K2, [$AC, " "]  ' Clear cell
    SEROUT TxPin, T19K2, [$99, $00]  ' Moves over another slot
    SEROUT TxPin, T19K2, [$AD, $01]  ' Show payload
    PAUSE PAUSEShort
    SEROUT TxPin, T19K2, [$99, " "]  ' Clear cell                   Step 7
    SEROUT TxPin, T19K2, [$AD, " "]  ' Clear cell
    SEROUT TxPin, T19K2, [$9A, $00]  ' Moves over another cell
    SEROUT TxPin, T19K2, [$AE, $01]  ' Show payload
    PAUSE PAUSEShort
    SEROUT TxPin, T19K2, [$9A, " "]  ' Clear cell                   Step 8
    SEROUT TxPin, T19K2, [$AE, " "]  ' Clear cell
    SEROUT TxPin, T19K2, [$87, $00]  ' Moves over another cell
    SEROUT TxPin, T19K2, [$9B, $01]  ' Show payload
    PAUSE PauseLong
    SEROUT TxPin, T19K2, [$8C, "HAPB"]  ' Show project Information  Step 9
    SEROUT TxPin, T19K2, [$9E, "Designed"]                        ' Step 10
    SEROUT TxPin, T19K2, [$B5, "By"]                              ' Step 11
    SEROUT TxPin, T19K2, [$C5, "Earl Foster"]                     ' Step 12
    PAUSE 2000                                 ' Keep splash screen active for 2 seconds
RETURN

' This procedure loops until the a valid position is received
' by the GPRMC "Status" string is obtained.  After GPS receives
' an "A" for valid position.
Seeking_Satellites:
DO
  SERIN GPSpin, N4800, 3000, No_GPS,[WAIT("GPRMC,"), SKIP 7, STR Char\1]       ' Get Status
  SEROUT TxPin, T19K2, [$0c]                 ' Clear LCD
  PAUSE 5
  SEROUT TxPin, T19K2, [$80, " Seeking Satellites"]
  PAUSE 200
  SEROUT TxPin, T19K2, [$80, "                   "]
  SEROUT TxPin, T19K2, [$94, " Seeking Satellites"]
  PAUSE 200
  SEROUT TxPin, T19K2, [$94, "                   "]
  SEROUT TxPin, T19K2, [$A8, " Seeking Satellites"]
  PAUSE 200
  SEROUT TxPin, T19K2, [$A8, "                   "]
  SEROUT TxPin, T19K2, [$BC, " Seeking Satellites"]
  PAUSE 200
LOOP UNTIL Char = "A"
SEROUT TxPin, T19K2, [$0c]                 ' Clear LCD
PAUSE 5
SEROUT TxPin, T19K2, [$A8, "Satellites Acquired"]
HIGH SatAcquired
PAUSE 1000
'SEROUT TxPin, T19K2, [$12]
RETURN

Show_Headers:
  SEROUT TxPin, T19K2, [$80, "Altitude: "]
  SEROUT TxPin, T19K2, [$94, "Time: "]
  SEROUT TxPin, T19K2, [$A8, "Lat: "]
  SEROUT TxPin, T19K2, [$BC, "Long:"]
RETURN

' No GPS detected, keep searching until found
No_GPS:
  SEROUT TxPin, T19K2, [$0c]                 ' Clear LCD
  PAUSE 5
  SEROUT TxPin, T19K2, [$80, "  No GPS Detected"]
  PAUSE 2500
  GOTO ProgramSetup

' Get the Altitude
' Altitude is a variable length field
' it follows the 8th comma in the GPGGA string
' which has variable length due to HDOP field having a variable field length.
' First Do loop finds the proper index starting point
' for the altitude by knowing that the altitude follows the 8th comma.
' Second Do loop finds the width of the field.  Fractional
' meters are not necessary in this project so the loop stops when it finds
' the decimal point.
' Note: fldWidth and Work is used twice to reduce the number of declarations in the program
Parse_GPS_Altitude:
   idx = 0 : fldWidth = 0
   DO
      GET idx, char
         IF char = "," THEN
            fldWidth = fldWidth + 1
            idx = idx + 1
         ELSE
            idx = idx + 1
         ENDIF
   LOOP UNTIL fldWidth = 8                          ' 8th comma found
   fldWidth = 0 : work = idx                        ' Reset fldWidth, idx is copied
   DO
      GET work, char                                ' Work is used to continue indexing
         IF char = "." THEN                         ' through the string until the period
            work = work + 1                         ' found.  As long as there is no period
         ELSE                                       ' the field width continues to increment
            fldWidth = fldWidth + 1
            work = work + 1
         ENDIF
   LOOP UNTIL char = "."
   GOSUB String_To_Value
   Altitude = Work
   IF Altitude < 1000 THEN
      TOGGLE LT0
      PAUSE 250
      TOGGLE LT0
      TOGGLE LT1
      PAUSE 250
      TOGGLE LT1
      TOGGLE LT2
      PAUSE 250
      TOGGLE LT2
      TOGGLE LT3
      PAUSE 250
      TOGGLE LT3
      TOGGLE LT4
      PAUSE 250
      TOGGLE LT4
      PAUSE 250
   ENDIF
RETURN

' Get the Latitude information
' hhmmss,ddmm.ffff,N,dddmm.ffff
' 01234567890123456789012345678
' numbers above are used for proper index value for fixed fields
Parse_GPS_Time:
  idx = 0 : fldWidth = 2                        ' Hours
  GOSUB String_To_Value
  UTC_HR = Work

  idx = 2 : fldWidth = 2                        ' Minutes
  GOSUB String_To_Value
  UTC_MN = Work

  idx = 4 : fldWidth = 2                        ' Seconds
  GOSUB String_To_Value
  UTC_SC = Work
RETURN

' Get the latitude
' North and South America are in the Northern Latitude Hemisphere
' therefore it is unnecesary to extract it from the string for
' for this project.
Parse_GPS_Lat:
  idx = 7 : fldWidth = 2                        ' Degrees
  GOSUB String_To_Value
  Degrees = Work

  idx = 9 : fldWidth = 2                       ' Minutes
  GOSUB String_To_Value
  Minutes = Work

  idx = 12 : fldWidth = 4                       ' Decimal Minutes
  GOSUB String_To_Value
  DMinutes = Work
RETURN

' Get the Longitude information
' North and South America are in the Western Longitude Hemisphere
' therefore it is unnecesary to extract it from the string for
' this project
Parse_GPS_Long:
  idx = 19 : fldWidth = 3                       ' Degrees
  GOSUB String_To_Value
  Degrees = Work

  idx = 22 : fldWidth = 2                       ' Minutes
  GOSUB String_To_Value
  Minutes = Work

  idx = 25 : fldWidth = 4                       ' Decimal Minutes
  GOSUB String_To_Value
  DMinutes = Work
RETURN

' Convert string data (nnnn) to numeric value
' idx      - location of first digit in data
' fldWidth - width of data field (1 to 5)
' Work     - returns numeric value of field
String_To_Value:
  Work = 0
  IF (fldWidth = 0) OR (fldWidth > 5) THEN String_To_Value_Done

Get_Field_Digit:
  GET idx, char                                 ' get digit from field
  Work = Work + (char - "0")                    ' convert, add into value
  fldWidth = fldWidth - 1                       ' decrement field width
  IF (fldWidth = 0) THEN String_To_Value_Done
  Work = Work * 10                              ' shift result digits left
  idx = idx + 1                                 ' point to next digit
  GOTO Get_Field_Digit

String_To_Value_Done:
RETURN