...another dumb question

nondem · 2007-12-08 01:27

I'm struggling with a variable issue. I've read the reference manual and a few things I googled. I'm still not having comprehension.

In a nutshell - I can't figure out how to wait for then accept a variable string from the serial port(of known length in characters NOT binary) then parse that string using the position of individual letters and their values to make decisions.
It's killing me. I'm not Vb guru by any means but I can easily parse a variable string in VB but not in PBASIC.

I've got a .NET application that talks to my BS2 via the serial port. It sends string commands to the BS2 that trigger subroutines.
For example:
I'd send "CB180" to the stamp which is waiting with:
SERIN 16, 16468, [noparse][[/noparse]WAIT("C"),serdata]

The feed that into some Select/Case and/or IF/THEN subs like this:
IF SERDATA(0) = "B" THEN
GOSUB Bearing:
GOTO MAIN:
ENDIF

IF serdata(0) = "D" THEN
GOSUB dt:
GOTO MAIN:
ENDIF

IF serdata(0) = "C" THEN
GOSUB camcontrol:
GOTO MAIN:
ENDIF

I've tried defining "serdata" w/various VAR types. Treating it as an array etc.

so anyway - "In theory" when I send "B180" to the serial port it SHOULD hit this particular if/then:
BEARING:
-
-
-
IF serdata = "B180" THEN
GOSUB TURNRIGHT
GOSUB TURNRIGHT
ENDIF
-
-
-
RETURN

The problem is that I get an "Expected THEN" highlighting the character after the B in B180.

I'm thinking this points to the variable expecting to be one letter long.

Thanks for reading this far [noparse]:)[/noparse]

-Randy

Mike Green · 2007-12-08 02:14

First of all, there are no string variables in PBasic. There are only arrays of characters (bytes). What you probably want is something like this:

letter var byte
number var word
...
SERIN 16, 16468, [noparse][[/noparse]WAIT("C"),letter,dec3 number]

You'd look at the 2nd letter by testing "IF letter = "B" THEN ..."
You'd look at the 3 digit value by testing "IF letter = "B" and digit = 180 THEN ..."

The description of SERIN and SEROUT describe the "formatters" like DEC3.
There's also some stuff in one of the appendices.
You can also use the STR formatter to read the next N bytes into a byte array.
That's more like what you were trying to do, but this may be easier.

nondem · 2007-12-08 06:07

Bingo - once again you saved me hours with your minutes. Thank you!

So everything is basically working...I'm getting close to having everything set up. VB console-app is working and I've got all the parts to build a power supply that will serve up 1 amp of 5vdc for the cam system using a relay that will be controlled by PIN8.

www.linearrow.com/consoleBeta.jpg - for a peak.

I do have one minor annoyance though. Commands generally have to be sent twice to the bot before it actually does something. The command is echo-ing back twice but only the second one triggers anything.
Any thoughts?

Here is the (roughly finished) code I'm using in the stamp:

' {$STAMP BS2}
' {$PBASIC 2.5}

pulsecount VAR Byte
letter VAR Byte
number VAR Word
dis VAR Word
distance VAR Byte

main:
'wait for command to be received

SERIN 16, 16468, [noparse][[/noparse]WAIT("C"),letter, DEC3 number]
'===============Determine Target of command
IF letter = "B" THEN
GOSUB Bearing:
GOTO MAIN:
ENDIF

IF letter = "D" THEN
GOSUB dt:
GOTO MAIN:
ENDIF

IF letter = "C" THEN
GOSUB camcontrol:
GOTO MAIN:
ENDIF

'==========================================

'===================Bearing Commands=======
bearing:

IF letter = "B" AND number = 000 THEN
GOTO main:
ENDIF
IF letter = "B" AND number = 045 THEN
GOSUB TURNRIGHT
ENDIF
IF letter = "B" AND number = 090 THEN
GOSUB turnRIGHT
GOSUB TURNRIGHT
ENDIF
IF letter = "B" AND number = 135 THEN
GOSUB turnRIGHT
GOSUB TURNRIGHT
GOSUB turnRIGHT
ENDIF
IF letter = "B" AND number = 180 THEN
GOSUB turnright
GOSUB turnright
GOSUB turnright
GOSUB TURNRIGHT
ENDIF
IF letter = "B" AND number = 225 THEN
GOSUB TURNLEFT
GOSUB TURNLEFT
GOSUB TURNLEFT
ENDIF
IF letter = "B" AND number = 270 THEN
GOSUB TURNLEFT
GOSUB TURNLEFT
ENDIF
IF letter = "B" AND number = 315 THEN
GOSUB TURNLEFT
ENDIF
PAUSE 20

SEROUT 16, 16468, [noparse][[/noparse]number , " - Bearing Command Received"]
RETURN

'===================DISTANCE Commands=======

dt:

'start of distance loop
IF letter = "D" AND number = 001 THEN
distance = 1
ENDIF
IF letter = "D" AND number = 002 THEN
distance = 2
ENDIF
IF letter = "D" AND number = 003 THEN
distance = 3
ENDIF
IF letter = "D" AND number = 004 THEN
distance = 4
ENDIF
IF letter = "D" AND number = 005 THEN
distance = 5
ENDIF
IF letter = "D" AND number = 006 THEN
distance = 6
ENDIF
IF letter = "D" AND number = 007 THEN
distance = 7
ENDIF
IF letter = "D" AND number = 008 THEN
distance = 8
ENDIF
IF letter = "D" AND number = 009 THEN
distance = 9
ENDIF
IF letter = "D" AND number = 010 THEN
distance = 10
ENDIF
distance = distance * 35
FOR dis = 1 TO distance
PAUSE 50
PULSOUT 13, 850
PULSOUT 12, 650
PAUSE 20
NEXT
PAUSE 20
SEROUT 16, 16468, [noparse][[/noparse]number , " - Distance Command Received"]

RETURN

'===============CAMCONTROL COMMANDS=============
camcontrol:
IF letter = "C" AND number = 666 THEN
HIGH 8

ENDIF

IF letter = "C" AND number = 667 THEN
LOW 8
ENDIF

PAUSE 20
SEROUT 16, 16468, [noparse][[/noparse]number , " - Camera Command Received"]
GOTO main

'============================================

'===============================SUBROUTINES

backward:

'___________________________________________________________________
'

Straight backward Continous
DO

PULSOUT 12, 850
PULSOUT 13, 650

PAUSE 20
LOOP

'___________________________________________________________________

RETURN

turnleft:
'___________________________________________________________________
'

90 degree left
FOR pulsecount = 1 TO 20

'PULSOUT 12, 850
PULSOUT 13, 650

PAUSE 20
NEXT

'___________________________________________________________________

RETURN

turnright:
'___________________________________________________________________
'

90 degree right

FOR pulsecount = 1 TO 20
PULSOUT 12, 850
'PULSOUT 13, 650

PAUSE 20
NEXT

'___________________________________________________________________

RETURN

Mike Green · 2007-12-08 06:41

The programming port (pin "16") always echos back to the PC. That's the way it's built.

You don't have to test letter again in your subroutines. You can take out the 'letter = "-" and' stuff.

Unsoundcode · 2007-12-08 18:04

I believe the reason you are having to send the information twice has something to do with the WAIT instruction at 9600 baud. If you drop to 4800 baud you may find it will work just fine. If you prefer to run at 9600 it is possible by using a different format string.

Stamp:
sData VAR Byte(4)
SERIN 16,16468,[noparse][[/noparse]WAIT("C"),STR sData \4\10]

VB:

Serialport.Write("C")

Thread.Sleep(5)

Serialport.WriteLine("B123")

I might also change my "wait" character to a character that I know is not going to appear in my data string, maybe WAIT("#") or some other non alphanumeric character.

Jeff T.

nondem · 2007-12-09 20:20

I'll be removing the lame redundant stuff and streamlining the code. Since with you guys help I've got it working - I'm back to working the "minor annoyances" checklist [noparse]:)[/noparse]

I'm stuck with minimum 9600 baud for now due to a limitation of my wireless-serial-port hardware. I'm using bluetooth com adapters till I can get some more robust hardware in.

Everything makes sense except the SERIN 16,16468,[noparse][[/noparse]WAIT("C"),STR sData \4\10] part. Actually I found reference to it but I can't figure out what \4\10 does.
I mean I see where stringin\10 would load a 10 byte array w/the string received but what does using two(\4\10) do?

Unsoundcode · 2007-12-10 00:10

When you read data into an array you can use the special formatter STR. This instruction requires you define the length of the string in other words the number of bytes you wish to place in the array. The first backslash is the number that defines those bytes which in our case is·four· ( \4 ). So if we send the four bytes "B527" from the VB application our array elements will contain sData(0)=B , sData(1)=5 , sData(2)=2 ,sData(3)=7.

The second backslash \10 is probably not needed in your case but defines a character that terminates the input before the defined length. In other words you could use the same instruction ,·even though you defined a length of four bytes , to recieve three bytes or less.
Without the termination character if you sent three bytes the SERIN would hang waiting for the fourth byte this would be overcome by sending the terminating character. The terminating character does not have to be 10 (NewLine) , it can be any character you want.

Jeff T.

EDIT : I liked the look of the interface BTW, especially the compass

Post Edited (Unsoundcode) : 12/10/2007 1:05:32 AM GMT

...another dumb question

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