How do I discern Maidenhead Locator from GPS lat long info.

[tasmod]

OK thanks for that I will look at it.

Meanwhile here is the full code i have for getting the NMEA data I want to display. NOTE the code for maidenhead is the same as above, a work in progress. All untested as yet.
I do have a fully working code in asm but wanted it in PBP for experimental purposes.

'
' Program to display returned value of a GPS on RB0
' LCD in 4-BIT mode PIC16F628 controller 4Mhz clock Fuse PWRT BODEN
' 
'GPS sentence: $GPRMC,192144.62,A,5041.6058,N,00412.6124,E,0.45,3 57.74,081205,,*0B

Define LCD_DREG PORTA          ' Port for LCD Data
Define LCD_DBIT 0                   ' Use upper 4 bits of Port  
Define LCD_RSREG PORTB         ' Port for RegisterSelect (RS) bit
Define LCD_RSBIT 4                 ' Port Pin for RS bit  (pin9)
Define LCD_EREG PORTB          ' Port for Enable (E) bit
Define LCD_EBIT 5                   ' Port Pin for E bit    (pin7)
Define LCB_BITS 4                   ' Using 4-bit bus
Define LCD_LINES 4                  ' Using 2 line Display
Define LCD_COMMANDUS 2000      ' Command Delay (uS)
define LCD_DATAUS 50              ' Data Delay (uS)

DEFINE OSC 4
CMCON = 7
OPTION_REG.7=0                 ' Enable Pull-Up's
GPSin VAR PORTB.0
LED  VAR PortA.4               ' flash per second

TRISA.0=0
TRISA.1=0
TRISA.2=0
TRISA.3=0

TRISA.4=0 ; LED

PAUSE 500

PORTA=0
PORTB=0

'Allocate Variables for GPS:
TimeOut CON 3000
baudGPS CON 24764 '16572 + 8192 (bit 13)

hh VAR BYTE           'hours
mm VAR BYTE          'minutes
knots VAR WORD     'speed in knots (units)
knotsten VAR BYTE   'speed in knots (tens)
course VAR WORD    'heading
latdeg VAR BYTE      'degrees latitude
latmin VAR BYTE      'minutes latitude
NS VAR BYTE          'north or south
londeg VAR BYTE     'degrees longitude
lonmin VAR BYTE     'minutes longitude
EO VAR BYTE          'east or west
j VAR BYTE             'day
m VAR BYTE            'month
a VAR BYTE            'year

fix VAR WORD        'GPS fix


LCDOut $FE, 1        'Clear Screen

LCDOut $fe,$80," GPS Decoder "
LCDOut $FE,$c0, " G8VLQ "
Pause 2000
LCDOut $FE, 1  

GPS:                 'read GPS

SerIn2 GPSin,baudGPS,Timeout,[wait("$GPRMC"),wait(","),DEC2 hh,DEC2 mm,wait(","),fix,wait(","),DEC2 latdeg,DEC2 latmin,wait(","),NS,wait(","),DEC3 londeg,DEC2 lonmin,wait(","),EO,wait(","),knots,wait("."),DEC2 knotsten,wait(","),DEC3 course,wait(","),DEC2 j,DEC2 m,DEC2 a]

flash:                       ;not accurate pps
led high
led low


IF fix="V" Then                                            'if no GPS fix
GOTO LCD1
EndIF

LCD:                  ; LATER put time and date on first line , remove names
                         ; callsign and QRA (maidenhead) on second line

LCDOut $fe,$80,"DATE: ",DEC2 j,"-",DEC2 m,"-",DEC2 a                                     ; 80 1st line   
LCDOUT $fe,$c0,"TIME: ",DEC2 hh,":",DEC2 mm                                                 ; c0 2nd line
LCDOut $fe,$94,"LAT:",DEC2 latdeg,",",DEC2 latmin," ",NS                                  ; 94 3rd line
LCDOut $fe,$d4,"LON:",DEC2 londeg,",",DEC2 lonmin," ",EO                                ; d4 4th line

GoTo GPS

LCD1:                       ; If invalid data, just shows gps string is received

LCDOut $fe,$80,"  Invalid data  "                                                                       ; 80 1st line
LCDOUT $fe,$c0,"     No Fix     "                                                                       ; c0 2nd line
LCDOut $fe,$94,"LAT:",DEC2 latdeg,",",DEC2 latmin," ",NS                                 ; 94 3rd line
LCDOut $fe,$d4,"LON:",DEC2 londeg,",",DEC2 lonmin," ",EO                                ; d4 4th line

GoTo GPS

locator:
     lonloc1=londeg + lonmin + 180
     lonloc2=lonloc1/20
     lonloc3=lonloc1//20
     maid1=lonloc2+1
     lookup maid1                         ; first main letter
     
     lonloc4=lonloc3//2
     maid3=lonloc3/2                      ;first number
     
     
     maid5=lonloc4*12+1
     lookup maid5                         ; 1st  2nd letter
     
     
     
     latloc1=latdeg + latmin + 90
     latloc2=latloc1/10+1
     latloc3=latloc1//10
     maid1=latloc2+1
     lookup maid2                         ; second main letter
     
     
     maid4=latloc3                        ; second number
     
     
     maid6=latloc3*24+1
     lookup maid6                         ; 2nd 2nd letter
     
     maidenhead=maid1, maid2, maid3, maid4, maid5, maid6
     
      

speed:
LCDOUT $fe,1
LCDOut $fe,$80,"SPEED :",knots,".",DEC2 knotsten," KNT"
LCDOut $fe,$c0,"HEADING:",DEC3 course," DEG"

END