file$ = "GPSLOG.LOG"
Open "COM3:19200,1024" As #1
Do
Line Input #1,msg$
Print msg$
Open file$ For append As #3
Print #3, MSG$
Close #3
Loop

file$ = "GPSLOG.LOG" ' initial filename
max =20
Dim arg$(max)

Open "COM3:19200,1024" As #1

Open file$ For append As #3
Do

nmea_sentence

'Print msg$
x$ = Input$(1, #1)
msg$ = msg$ + x$
x$ = Input$(1, #1)
msg$ = msg$ + x$

If arg$(0) = "GPRMC" Then
Print msg$
file$ = arg$(9) + ".LOG"
GoTo savefile
EndIf

If arg$(0) = "GPGGA" Then
Print msg$
GoTo savefile
EndIf

Rem save to SD card

GoTo andrew

savefile:

'file$ = arg$(9) + ".LOG"
'Open file$ For append As #3
Print #3, MSG$
'Close #3



andrew:

Loop

Rem -- SUBS --


Sub nmea_sentence
Do
msg$ ="$" ' subroutine start
Do While Input$(1, #1) <> "$" : Loop ' wait for the start
For i = 0 To max
arg$(i) = "" ' clear ready for data
Do ' loops until a specific exit
x$ = Input$(1, #1)
' Print x$
msg$ = msg$ + x$ ' get the character
If x$ = "," Then Exit ' new data field, increment i
If x$ = "*" Then Return ' we have all the data so return
arg$(i) = arg$(i) + x$
'Print arg$(i) ' add to the data
Loop
'Print arg$(i) ' loop back for the next char
Next i ' move to the next data field
' Print "Corrupt data..." ' exceeded max data items
'Print msg$
Loop

End Sub