CByte keyword?

[Tim Seyfarth]

I am a newbie to PB. My first effort with PB involves sending/receiving
data through a Com port. The data is sent in hex format. In VB you can
convert an integer value to a byte value using CByte(integer). How is
this addressed in PB and where in the book can I find it? I have
searched everywhere!

Thanks
Tim

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[Mel Bishop]

I'm not quite sure I fully understand the question but here's my
best guess:

If you have an ASCII value or HEX string that you need sent over
the comm port, you need to convert it to a CHR$() for transmission.
Example...

Assuming you have your comm port opened as #1

t$ = "The Quick Brown Fox"
for x = 1 to len(t$)
h = asc(mid$(t$,x,1)) '<==> The ASCII value for the letter
print #1,chr$(h);
next x

A more efficient example, however, would be deleting line 3 and
replace line 4 with:

print #1,mid$(t$,x,1);

This example should be relevent for just about any occurance
you would run across.

Hope this helps. If it doesn't, how about posting a snippet
of what you are trying to accomplish and let's go from there.


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[This message has been edited by Mel Bishop (edited April 08, 2002).]

[Buck Huffman]

I believe the CBYT function is what you're looking for. You can
find the description in the PowerBasic Reference Guide under the
heading CBCD, CBYT, CBDL, etc... . That's on page 59 of my manual
(not sure if they're all the same )

works like this
bytevar? = CBYT(anynumber)

you really shouldn't need this though, according to the manual
PB converts this automatically. like this.

thisbyte? = yourinteger%

haven't tried it, should work though


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[Tim Seyfarth]

This is where I am really confused... I am assembling a string
byte values that will need to be sent out through the COM port.
The size is always greater than 5 byes (there are actually seven
parts that make up the byte string).

So I guess there are 3 questions:
1. Is it appropriate to use a byte array
2. Is it more appropriate to use a var dimensioned as byte but how do you set the length?
3. When ready to send to the serial port then it have to do
something like Print #1,chr$(bytevar)

Thanks everyone!
Tim

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[Lance Edmonds]

It would be easiest to use a dynamic string, thus:

A$ = CHR$(65,66,67,68,69,70,71) ' or use "abcedf", etc
PRINT #1, A$

You could use a byte array, but you'd then have to reference each byte individually to construct the 7 byte sequence... hence, using a dynamic string is the easiest way.

Another approach is to use a combination of both methods, using a UNION... a brief example of the concept follows:

UNION commtype
  bData(1 TO 7) AS BYTE
  sData AS STRING * 7
END UNION
 
DIM x AS commtype
FOR z% = 1 TO 7
  x.bData(z%) = 64 + z%
NEXT z%
...
PRINT #1, x.sData

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>