'-------------------------------------------------------------------------
' UNIVERSAL RS232 PROTOCOL: VERSION4.BS2
'-------------------------------------------------------------------------
'         BASIC STAMP-2 RS232 Communication Protocol Version 4.0  
'                             14 JUNE 1998
' Program by:  Gerald Rutherford    RUTHVEN@SWBELL.NET     (314)-429-0827
'------------------------------------------------------------------------- 
' With this program loaded into the BASIC Stamp-2 you will be able to
' send and retrieve data with a host PC. Communications is via Pin-16
' of the Stamp-2. Ensure that the ATN signal is NOT connected.
'
' This program was designed to operate with my VER4.BAS Qbasic 4.5
' driver software or your own program using the version-4 protocol.
' The protocol has been developed as shareware, you may use it in your
' own programs freely. 
'
' Leagal stuff: I am not responsible if you fry your computer or stamp!
'-------------------------------------------------------------------------
' Protocol:     1) STAMP waits for CMD header followed by D1, D2, and D3
'                  in ASCII BINARY format. "CMDaabbcc" (See note)
'               2) STAMP processes the data depending on the command 
'                  embedded in D1 [ D1H ].
'               3) When completed, it will send the RDY header,
'                  then D1, D2, and D3 in ASCII BINARY format.
'               4) STAMP will return to step 1 for next command from 
'                  the host PC.
'               5) In the event of a Reset, the stamp will return a
'                  RST header to inform the PC that a command was missed
'                  or that the STAMP just came online.
'
'       NOTE:   The ASCII letters "CMD" are sent to the STAMP along with
'               three numbers that are sent as 3 sets of 2 BYTEs each.
'               there are no spaces, commas or other delimiters.
'-------------------------------------------------------------------------
START:                  ' Beginning of programming code.
'-------------------------------------------------------------------------
'                         VARIABLE LIST FOLLOWS           
'-------------------------------------------------------------------------
BAUD CON 84             ' RS232 baud rate constant. (9600 baud)
D1 VAR WORD             ' Transfer - Command (byte) and modifier. (byte)
D2 VAR WORD             ' Transfer - Generic variable. (word or 2 bytes)
D3 VAR WORD             ' Transfer - Generic variable. (word or 2 bytes)
D4 VAR BYTE             ' Internal - Generic variable. 
D1H VAR D1.BYTE1        ' First  Byte of D1 : Command Number
D1L VAR D1.BYTE0        ' Second Byte of D1 : Pin or Modifier Number
D2H VAR D2.BYTE1        ' First  Byte of D2 : Unassigned 
D2L VAR D2.BYTE0        ' Second Byte of D2 : Unassigned
D3H VAR D3.BYTE1        ' First  Byte of D3 : Unassigned
D3L VAR D3.BYTE0        ' Second Byte of D3 : Unassigned
'-------------------------------------------------------------------------
FREQOUT 15,50,800                                ' Only a Hard RESET
FREQOUT 15,50,1200                               ' will do this part 
SEROUT 16,BAUD,1,["RST",D1H,D1L,D2H,D2L,D3H,D3L] ' of the program.
'-------------------------------------------------------------------------
RESET:                  ' Soft-reset by setting all pins, and variables
DIRS=0                  ' to zero or other default variable. This should
OUTS=0                  ' stop any motors or other devices if programmed
INS=0                   ' properly. 
D1=0                    '
D2=0                    '
D3=0                    '
D4=0                    '
FREQOUT 15,100,2400     ' 
'--------------------------------------------------------------------------
POINT1:                 ' Send header and data to host.
D4=0                    ' 
SEROUT 16,BAUD,1,["RDY",D1H,D1L,D2H,D2L,D3H,D3L]
'-------------------------------------------------------------------------
POINT2:                 ' Sit around waiting for the PC to call.
SERIN 16,BAUD,30000,POINT2,[WAIT("CMD"),D1H,D1L,D2H,D2L,D3H,D3L]
D4=D1H                  ' We got a command so let's process it!
'-------------------------------------------------------------------------
POINT3:                 ' Determine which command was sent.
BRANCH D4,[RESET,JUMP01,JUMP02,JUMP03,JUMP04,JUMP05]
D4=D4-5                 ' Calculate next 5 commands.
BRANCH D4,[RESET,JUMP06,JUMP07,JUMP08,JUMP09,JUMP10]
D4=D4-5                 ' Calculate next 5 commands.
BRANCH D4,[RESET,JUMP11,JUMP12,JUMP13,JUMP14,JUMP15]
'                       ' Not any command from 0 to 15.
'-------------------------------------------------------------------------
POINT4:                 ' Undefined command was sent.
GOTO POINT1:            ' Ignore and get next valid command.
'-------------------------------------------------------------------------
JUMP01:                 ' #1 Make a high tone on pin 15 via speaker.
FREQOUT 15,10,2000      ' Just an example code for prototype.
GOTO POINT1             ' (Remove and insert your code here.)
'-------------------------------------------------------------------------
'                       Commands #2 through #15 are ready for your
'                       programming applications.
'-------------------------------------------------------------------------
JUMP02:                 ' 
JUMP03:                 ' 
JUMP04:                 '
JUMP05:                 '
JUMP06:                 '
JUMP07:                 '
JUMP08:                 '
JUMP09:                 '
JUMP10:                 '
JUMP11:                 '
JUMP12:                 '
JUMP13:                 '
JUMP14:                 '
JUMP15:                 ' 
'-------------------------------------------------------------------------
GOTO POINT1             ' Start over, wait for another command.
'-------------------------------------------------------------------------
END                     ' You should never get here... ever.
'-------------------------------------------------------------------------