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**Mel Bishop** · 21 Sep 2005, 11:35 AM

The only thing I can think of is trying to set the baud rate and
opening the port using ASM. Non-standard baud rates, to the best
of my knowledge is not possible using standard PB function(s).

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**Paul Dixon** · 21 Sep 2005, 12:09 PM

William,
I'd have thought you'd just need to open the port using "OPEN COM.." choosing parameters to get it as close as you can to the desired rate.
Then write the values you really need directly into the UART registers using INP and OUT. It sounds like you know how to use the UART on a PC clone so it's exactly the same as PB runs that same UART chip in a PC clone.

Paul.

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**Aldo Cavini** · 22 Sep 2005, 01:15 AM

William, just open the COMx with the standard PBDOS statement, then OUT the corret divisor value to the UART. Of course you need not to be running on a NT platform, since OUTs are prohibited.

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**Donald Darden** · 30 Sep 2005, 06:23 PM

Dividing 115,000 by some integer to derive a baud rate is the
method required. The rate of 8214 (115,000 / 14) is as close as
you can get, and will likely work. You need to use the COMM OPEN
statement, during which you can send a number of optional
parameters to the UART, including baud rate and control signal
settings. PB Help files go to some length to try and steer you
in the right direction, but it does not hurt to consult another
source of RS-232, Serial, or Modem communications. Note that not
all serial connections or cables are alike, and this means that
you may have experiement a bit with enabling or disabling some
of the signales to get it to work right.

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Old Navy Chief, Systems Engineer, Systems Analyst, now semi-retired

**William Haynes** · 30 Sep 2005, 07:23 PM

Donald, thank you for the post. I can not find the "COMM OPEN" in either
of my PowerBasic books (User Guide or Reference Guide) can you
point me to info on the command? It sounds like it's just what
I'm looking for.

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**Donald Darden** · 2 Oct 2005, 07:47 PM

Sorry, that was a split-off with the new PB/CC command syntax.
You would still use OPEN "COM1:yadda,yadda,yadda" in PB/DOS.
All you need to do is figure out what to put in for the yaddas.

This is an extract from the PB/DOS Help Files, under OPEN:

The keyboard, screen, printers, and communications ports may be opene
as files using filenames "KYBD:", "SCRN:", "CONS:", "LPT1:", "LPT2:",
"LPT3:", "COM1:", "COM2:", "COM3:", and "COM4:". "KYBD:" and "CONS:"
use DOS for all I/O, allowing both input and output to be redirected.
"SCRN:" writes to the screen memory directly, preventing redirection.
Access and Lock network modes may be specified when using DOS 3.0 or
later. 'access' is one of READ, WRITE, or READ WRITE. lock is either
SHARED, LOCK READ, LOCK WRITE, or LOCK READ WRITE. Specifying ACCESS
READ means that only subsequent read operations will be allowed on th
file; attempting a write operation will cause an error. ACCESS WRITE
allows only write operations, while ACCESS READ WRITE allows both. LO
WRITE means that this file cannot be written to by other users while
have it open; an attempt to do so will generate an error for the othe
user. The file can still be read by another user, however.

Note that I mentioned that PB does cover serial communications in
some debth, but more so with PB/CC and PB/Win. Back when PB/DOS
had its heyday, modem communications was a lot more prevalent
than today, and you usually were expected to just refer to the
modem handbook as to how to set up the COM port, which represented
both the UART and the Modem proper (The UART was the serial port
circuitry, and the Modem was the communications device for
communicating over standard phone lines. For some installations,
the functions were consolidated into one).

Note that the UART and the Modem speeds do not have to correspond
to each other. The near and distant modems connect and exchange
information using their own protocols, compression and decompression
algorythms. and follow standards such as v.42, V.80, V.90, and
V.92. It is a frequent habit to set the UART speed to a higher
rate, such as 115,000 for a 56 KB connection, on the expectation
that the PC will service the connection more frequently and reduce
the likelihood of a communications error.

Here are some links that may be of some value: http://www.uktsupport.co.uk/reference/modem.htm http://www.computerhope.com/atcom.htm http://www.sixnetio.com/htmlhelps/vtmodem/5a78555.htm http://www.sixnetio.com/htmlhelps/vtmodem/5a6804f.htm http://zone.ni.com/devzone/conceptd....6F6A007F154C#6 http://news.managingautomation.com/fullstory/452471 http://www.docklight.de/manual/index...ctsettings.htm http://www.hallogram.com/commdrv/libfeat.html http://www.sinnovations.com/htdocs/s...2_analyzer.htm http://www.commtech-fastcom.com/Data...324PCI335.html
GetCommModemStatus http://www.geocities.com/terminalplus/ http://www.amplicon.co.uk/dr-prod3.c...upId/10795.htm http://www.digibuy.com/cgi-bin/produ...l?109311792044

Because modem developers often pursued the path of trying to
provide advance features for their modems that exceeded those
of their rivals, all modems tended to follow the Hayes AT
command set and lower register designations, but went in different
directions beyond that point. So for advance features, you
usually had to refer to specific documentation for a given
model or family of modems. Note that modems are usually
programmed or modified as to their settings after the COM port
has been opened, using special ASCII command strings.

If you are trying to connect directly to a COM port without the
involvement of a modem, you are limited to what commands can be
recognized by the UART and communications program, and the fact
that the UART is controlled through certain I/O registers that
correspond to addresses associated with that COM port. These
are easily modified in DOS, but 32-bit Windows does not want to
give the user ready access to these locations.

There are two approaches to this problem: The first is to look
for software that circumvents Windows, opening the COM ports so
that you can manipulate them. The second way is to acquire a
serial interface card that is specifically designed to work in
Windows and which gives you added control, including nonstandard
baud rate settings. The links above include references to both
approaches. I personally have liked the COMM-DRV libraries,
which I first encountered through the 3rd party offerings on
this web site.

I should have said that there is a third way, which is the
Windows way. Now I know that PB/DOS developers are not really
into Windows API calls, but there is a knowledge section on
working with COMM devices at this location:
http://msdn.microsoft.com/library/de..._functions.asp

The idea of course is that you can either go this course yourself,
or you can get a comm library (DLL) that handles the comm port
settings under Windows for you. In addition, there are products
that offer a combined hardware/software solution.

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Old Navy Chief, Systems Engineer, Systems Analyst, now semi-retired

**Scott Turchin** · 18 Oct 2005, 04:03 PM

Wow that brings back some memories!
Since my app was configurable from INI files this is how I did it:
Obviously BaudRate$ is set as you please, and the N,8,1 part you will have to set according, likely what, P,8,0? I'm not sure - been a while since I messed with synchronous stuff.....

This app listened for a RING, below I will post some code for ya as well in case you want it.

Code:

If IRQ=3 Or IRQ=4 Then
        COMOPEN$="COM"+Left$(Comport$,1)+":"+Left$(BaudRate$,5)+",N,8,1"
Else
        COMOPEN$="COM"+Left$(Comport$,1)+":"+Left$(BaudRate$,5)+",N,8,1,IR"+LTrim$(Str$(IRQ,1))
End If   'The else sets for funky irq's...      

hCom = Freefile
Open ComOpen$ as #hCom

That was the basics.
'
'
'

Function Carrier( ByVal Port% ) PUBLIC
  If Port% < 1 Then
    Carrier = 0
    Exit Function
  End If
  Local Status

  ! push DS; save DS for PowerBASIC

  ! mov BX, Port%; put port number in BX
  ! shl BX, 1; multiply it times 2
  ! add BX, &H3FE; add 3FEh to it
  ! xor DX, DX; access bios data area
  ! mov DS, DX; put segment into DS
  ! mov DX, DS: [BX]; get port address
  ! add DX, 6; status register at offset 6
  ! in AL, DX; get status byte into AX
  ! mov CL, 7; we want bit 8
  ! shr AX, CL; shift it into place
  ! and AX, 1; isolate first bit
  ! neg AX; convert to 0 or - 1
  ! mov status, AX; put into temp variable

  ! pop DS; restore DS for PowerBASIC

  Carrier = Status

End Function
'------------------------------------------------------------------------------
Function CtsStatus( ByVal Port% ) PUBLIC

  Local Status

  ! push DS; save DS for PowerBASIC

  ! mov BX, Port%; put port number in BX
  ! shl BX, 1; multiply it times 2
  ! add BX, &H3FE; add 3FEh to it
  ! xor DX, DX; access bios data area
  ! mov DS, DX; put segment into DS
  ! mov DX, DS: [BX]; get port address

  ! add DX, 6; status register at offset 6
  ! in AL, DX; get status byte into AX
  ! mov CL, 4; we want bit 5
  ! shr AX, CL; shift it into place
  ! and AX, 1; isolate first bit
  ! neg AX; convert to 0 or - 1
  ! mov status, AX; put into temp variable

  ! pop DS; restore DS for PowerBASIC

  CtsStatus = Status

End Function

'------------------------------------------------------------------------------
Function DtrStatus( ByVal Port% ) PUBLIC
  If Port% < 1 Then
    DtrStatus = 0
    Exit Function
  End If
  Local Status

  ! push DS; save DS for PowerBASIC

  ! mov BX, Port%; put port number in BX
  ! shl BX, 1; multiply it times 2
  ! add BX, &H3FE; add 3FEh to it
  ! xor DX, DX; access bios data area
  ! mov DS, DX; put segment into DS
  ! mov DX, DS: [BX]; get port address

  ! add DX, 4; status register at offset 4
  ! in AL, DX; get status byte into AX
  ! and AX, 1; isolate first bit
  ! neg AX; convert to 0 or - 1
  ! mov status, AX; put into temp variable

  ! pop DS; restore DS for PowerBASIC

  DtrStatus = Status

End Function
'------------------------------------------------------------------------------
Function Ring( ByVal Port% ) PUBLIC

  Local Status
  ! push DS; save DS for PowerBASIC
  ! mov BX, Port%; put port number in BX
  ! shl BX, 1; multiply it times 2
  ! add BX, &H3FE; add 3FEh to it
  ! xor DX, DX; access bios data area
  ! mov DS, DX; put segment into DS
  ! mov DX, DS: [BX]; get port address
  ! add DX, 6; status register at offset 6
  ! in AL, DX; get status byte into AX
  ! mov CL, 6; we want bit 7
  ! shr AX, CL; shift it into place
  ! and AX, 1; isolate first bit
  ! neg AX; convert to 0 or - 1
  ! mov status, AX; put into temp variable
  ! pop DS; restore DS for PowerBASIC

  Function = Status

End Function

------------------
Scott Turchin
MCSE, MCP+I
Computer Creations Software
http://www.tngbbs.com/ccs

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Non-standard baud rates

Non-standard baud rates

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