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Hi, I need to find out what these lines of code are doing? The purpose of the code is to get information from a machine via RS232. The string of information this prog is getting, is being manipulated but I can't figure out what hell its doing to the string? I'm not a QBasic programmer so Any help explaining these 6/7 lines would be appreciated. Thanks in advance.
'Read from inst
'---------------------------------------
OPEN "COM1:9600,S,7,1,CD0,CS0,DS0,OP0,RS" FOR RANDOM AS #1
c1! = 0
c1$ = ""
s1$ = ""
a$ = CHR$(27) + "P": PRINT #1, a$
s1$ = "": c1$ = ""
a$ = INPUT$(15, #1)
CLOSE
s1$ = LEFT$(a$, 1)
c1$ = MID$(a$, 3, 8 )
c1! = VAL(c1$) 'inst value
IF in = 2 THEN c1! = c1! * 10
IF s1$ = "-" THEN c1! = -c1! 'Convert to -ve val if -sign
RETURN
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Qbasic Rs232 Code Explanation
Need to find out what this code os doing??
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#2
iccaros 
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Posted 30 November 2007 - 04:39 PM
Line one of the "Function" is opening the rs232 FIFO and assigning its buffer the name #1 reading in random mode and not sequencal
next they are creating an integer and two strings.
next comes the work
a$ = CHR$(27) + "P": PRINT #1, a$
this is really two lines in one see the :
so we assign ascii char 27 (see http://game-editor.c...ages/ascii.jpg) followed by the P
so we have a$ = "^[P"
and the second half puts that string to the serial port (in basic you print to a port like you do the screen, and read from it like a keyboard)
s1$ = "": c1$ = ""
this is also two lines that assign blank strings to s1$ and c1$
it looks like (with out the rest of the code this is just a guess)
a$ = INPUT$(15, #1)
is assigning the first 15 chars from the serial port to a$
or INPUT$ is an Array and we are looking up a value that is at position 15 x the value on the serial port
then close does what it says , it closes the serial port
the rest is simple
s1$ = LEFT$(a$, 1)
assign the value of the array LEFT$ at position of value of a$ x 1
c1$ = MID$(a$, 3, 8 )
again assign c1$ the value from an array based on the value of a$
c1! = VAL(c1$) 'inst value
change string c1$ to an integer
IF in = 2 THEN c1! = c1! * 10
I assume this is correct for qbasic but in other languages its IF in == 2 Then, so we evaluate the value of 'in' and if it equals 2 then we multiply 10 to c1! and assign that value back to its self
IF s1$ = "-" THEN c1! = -c1! 'Convert to -ve val if -sign
check if s1$ = - and if so make c1! a negative number
hope that helps..
next they are creating an integer and two strings.
next comes the work
a$ = CHR$(27) + "P": PRINT #1, a$
this is really two lines in one see the :
so we assign ascii char 27 (see http://game-editor.c...ages/ascii.jpg) followed by the P
){kind=link}
so we have a$ = "^[P"
and the second half puts that string to the serial port (in basic you print to a port like you do the screen, and read from it like a keyboard)
s1$ = "": c1$ = ""
this is also two lines that assign blank strings to s1$ and c1$
it looks like (with out the rest of the code this is just a guess)
a$ = INPUT$(15, #1)
is assigning the first 15 chars from the serial port to a$
or INPUT$ is an Array and we are looking up a value that is at position 15 x the value on the serial port
then close does what it says , it closes the serial port
the rest is simple
s1$ = LEFT$(a$, 1)
assign the value of the array LEFT$ at position of value of a$ x 1
c1$ = MID$(a$, 3, 8 )
again assign c1$ the value from an array based on the value of a$
c1! = VAL(c1$) 'inst value
change string c1$ to an integer
IF in = 2 THEN c1! = c1! * 10
I assume this is correct for qbasic but in other languages its IF in == 2 Then, so we evaluate the value of 'in' and if it equals 2 then we multiply 10 to c1! and assign that value back to its self
IF s1$ = "-" THEN c1! = -c1! 'Convert to -ve val if -sign
check if s1$ = - and if so make c1! a negative number
hope that helps..
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