FTDI FT232BM Hyperterminal Problems

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Hi.  I'm working on a project where I am connecting a Garmin OEM GPS
Receiver (asynchronous, RX-TX-GND) through the USB port in Windows XP.
Initially I connected the GPS through COM1 and successfully received
the data in HyperTerminal.  The GPS sends data at the factory default
of 4800, 8N1.  The GPS sentence length is 55 bytes plus a LF and CR at
the end, one sentence per second. (only the $GPGGA sentence)

Now I am trying to receive the same data via the USB port using a DLP
Design DLP-USB232M USB Adapter.  I downloaded the Virtual Com Port
(VCP) drivers and installed them.  The installed drivers show up in
the device manager as "USB Serial Port (COM4)".  It is set to 4800,
8N1 under Properties.

When I try to connect to COM4 in HyperTerminal, I only receive
garbage.  The data displayed in the HyperTerminal window does not
resemble the data seen from the connection on COM1 and is not the same
length.

I ran "Test Application V1.0" from DLP and when connected to COM1 it
receives 113 bytes of data at a time.  When connected to COM4, 113
bytes are also received.

The DLP board is seated in a solderless breadboard.

Does anybody know what might be going on?

C. Bremer

Re: FTDI FT232BM Hyperterminal Problems
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Try RealTerm (it's free). It's much better than Hyperterminal for sorting
out comms problems.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller



Re: FTDI FT232BM Hyperterminal Problems
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I downloaded Realterm and I get pretty much the same results.  COM1
works fine but COM4 (USB VCP) is still garbage.

On the bottom right, the indicators for 'BREAK' and 'Error' are both
red for COM4 but not for COM1.  Can somebody point me to more info on
what these mean or more documentation for Realterm?

Also, I receive 57 bytes at a time on COM1 (which is good) but 58
bytes on COM2 (which is bad).  And the HEX data is very different.
I've tried writing the raw HEX out in binary to find some sync.
problem, but to no avail.

Any suggestions?

Re: FTDI FT232BM Hyperterminal Problems
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Sounds like you have at least one of baudrate, parity, stop-bits
mis-set.

--
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 the broken "Reply" link at the bottom of the article.  Click on
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Re: FTDI FT232BM Hyperterminal Problems
On 26 Feb, in article

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Personally this suggests you have not interfaced to the RS232/USB
correctly as it looks like the signal is inverted somewhere, hence the
break condition.

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How is the RS232 conversion done?
How is the serial data connected between your micro and the USB
adapter?

Suggests an inversion somewhere.

--
Paul Carpenter          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
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Re: FTDI FT232BM Hyperterminal Problems
paul$@pcserv.demon.co.uk (Paul Carpenter) wrote in message
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Thank you.  This was exactly the problem.  The micro (GPS) output is
GND to 5V with the line idle output of the GPS being GND.  I inverted
the output of the GPS with a 74LS04 (overkill, I know) and now the
RS232/USB (FT232BM/DLP-USB232M) interface works great.
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Re: FTDI FT232BM Hyperterminal Problems
On 27 Feb, in article

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Well if you need a single inverter and you have no spare PLD/CPLD/FPGA
pins available, you could look at 74AHCT1G04GW single inverter in SOT23-5
Also called Picogate and made by Philips and TI.

I have used them for applications with a micro and NO PLD that needed a
couple of gates, so made life a whole lot easier. Even breadboarded onto
stripboard for tests.

--
Paul Carpenter          | snipped-for-privacy@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/ PC Services
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Re: FTDI FT232BM Hyperterminal Problems
paul$@pcserv.demon.co.uk (Paul Carpenter) wrote in message
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sorting
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I took out the 74LS04 and replaced it with a 2N3904 connected as a
common emitter.  Only needed 2-10k externals.

C. Bremer

Re: FTDI FT232BM Hyperterminal Problems

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XP.

I also found HyperTerminal hopelessly buggy and unusable; in addition
to Leon's suggestion I can recommend Takashi Teranishi's Tera Term
(Pro): http://hp.vector.co.jp/authors/VA002416/teraterm.html which
worked perfectly for me.

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Re: FTDI FT232BM Hyperterminal Problems

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When you start your HyperTerminal, click Call -> Disconnect, then click
File -> Properties then confirm you're using the com port you think you are.
Next click the Configure button and confirm the baud setting are correct for
your interface.  Make sure you select None for Flow Control.  Save
everything then click Call -> Call.  It should be OK.

I've run through this a few times in trying to get a HyperTerminal session
working correctly.  I have successfully gotten an FTDI / USB adapter to work
with the three wire serial interface to a GPS at 4800N81.

HTH

Dave



Re: FTDI FT232BM Hyperterminal Problems
i use the fdti chipset for com with and without hyperterminal , conclusion
no problem , i also use an usb dual serial adapter with 2 ftdi , and i have
the same conclusion.
Perhaps , effectively the bug with hyperterminal when changing the
parameters and not connect and disconnect , but this bug is with all sort of
com .
i try to avoid the usb serial behind usb HUB , because i get some energy
economy disconnect , that all.
in particular i use picstart plus on com3 and prototype board on com4.


snipped-for-privacy@posting.google.com...
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Re: FTDI FT232BM Hyperterminal Problems

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<Egg suck>
Have you checked the signal levels to the DLP-USB232M, looking at them on a
scope? What RS232 level converter are you using?

</Egg suck>

As others have posted, I find that TeraTerm is much better for serial
communications debugging than HyperTerminal. portmon (www.sysinternals.com)
is very good for diagnosing problems too when you are writing the Windows
comms. code.

    Andrew



Re: FTDI FT232BM Hyperterminal Problems
also, chekout TeraTerm !

Laurent Gauch
www.amontec.com

C Bremer wrote:
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Re: FTDI FT232BM Hyperterminal Problems
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Agreed!
Another thing against Hyperterminal: try opening a port while data comes in
from a device: HT will tell you it cannot open the port 8 out of 10 times!

Meindert



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