Problem with USB port

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I'm in clinical research at a large medical school and a technician
who has designed a device for us needs help.

He's working with a FTDI UM245R USB development
module with a Microchip PIC microprocessor to input
ADC data to a Windows XP pc. The PIC chip, after initializing
handshaking with the UM245R, just dumps data to the port.
The USB port is configured as a serial port COM3. It worked OK
on a breadboard circuit, but now in a hard wired circuit, after
registering the USB port, the USB port shows only CTS (clear to send)
and null characters.  What could the problem be?


Any help would be greatly appreciated. It's a prototype cardiology
device and may save many lives.

Thanks in advance

Josh




Re: Problem with USB port
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Hello Josh,

Do you have a schematic you can post somewhere ??

donald

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Surely at the cost a of a great many dollars? Saving lifes has gotten pretty
expensive lately...



Re: Problem with USB port

On Thu, 16 Oct 2008 11:23:55 -0500, "Jon Slaughter"

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A particularly scary post... the skill set represented belongs, at
best, on sci.electronics.basics :-(

                                        ...Jim Thompson
--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Thanks for your cynical replies. We have been working on this device for over
11 years using our own money to fund the development of the device. It's
more than 99% complete with the exception of the final interface problem
our techncian has with the PC. I am very serious about this and am saddened
at the level of discourse here.

If this problem isn't solved, there's no cardiac device.

Dr. Josh Backon
snipped-for-privacy@vms.huji.ac.il


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Dr Josh,

Please do not take this personally.

This is Usenet, there are all sorts of lame ideas posted here.

We (they) didn't know if your post was sincere or not.

Please post a schematic somewhere and we can look at it.

donald

Re: Problem with USB port


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I have so advised the doctor, by phone.  He's going to get direct
detail from the electronics technician.

                                        ...Jim Thompson
--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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I got a new motto for there products: "Saving lives, at a price."



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Sorry for my off-color jokes too.  But seriously, you might be better
off dealing with a single USB micro than a pair of problems (FTDI <->
PIC).  Believe me, they will be pointing fingers at each other.

USB is complicated enough without the synchronization issues between
two chips.  I am currently using AT90USB82,162 and 646.  Codes that
works under RC stops working under crystal, just as an example.


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Pay no attention to JT - he's just a cantankerous old billy goat who's
pissed off that people have noticed what a dork Dubya is. And the
McCheney^H^H^H^H^H^HCain/Tina Fay candidacy has to be giving him ulcers.

As Jim would say if for example, I was in such a state, "Bwahahaha!" >:->

Good Luck!
Rich


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As much as I hated to defend JT, he followed up and even called the
doctor.

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   Not when one can print a few hundred billion dollars more...

Re: Problem with USB port
Ditch the pic, Port him to a Atmel Mega8 series and use Objective
Developments USB code. Its known to work.
http://www.obdev.at/products/avrusb/index.html

Having spent the last few months developing a USB 12 bit joystick for
a flight simulator , I can personally attest there is a lot of USB
garbage out there, most of it poorly documented and  poorly tested.

Steve Roberts

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they guy's using a usb to serial interface chip and it's not running
right, the problem's not usb code in the pic as there is none,
possibly it's a crystal or other capacitance sensitive part
that's misbehaving now the circuit's out of breadboard.

I'm glad to hear your reports on avrusb as I have a project for which it
seems ideal myself...

Bye.
   Jasen

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The software USB is another can of worms.  Timings is very critical
and only work on low speed USB.

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It's most likely software problem with the FTDI245.  The FTDI245 does
not have A2D and the PIC does not have USB.  However, there are plenty
of other chips with  A2D and USB.  That's why I said it was the
technician's problem of picking parts, and the managing doctor's
problem of not evaluating other options.

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I suggest ATmega16U with 16K Flash, 1K Sram, 12 10 bits A2D and USB
2.0.
Life is too short to deal with other sub-standard parts.

Re: Problem with USB port
On Fri, 17 Oct 2008 02:21:45 -0700, Robert Baer

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Printed dollars, hah!  Most of the "money" circulating today is just
computer data.  The printing is no more than computer data entries.
  

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Which one?  I'll tell all my friends and families to stay away.

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The technician?

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Or kill some.

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OK, guys.  I just got off the phone with the cardiologist.  This is
for real, just a problem with communicating what an electronics
technician told the doctor.  Sounds like a USB driver issue, which is
outside my realm of expertise... I only speak transistors ;-)

Watch for a re-post with DETAILS.  The doc needs help.  Thanks!

                                        ...Jim Thompson
--
| James E.Thompson, P.E.                           |    mens     |
| Analog Innovations, Inc.                         |     et      |
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Best to email FTDI
I'm using the FIFO version OK and have modified one of their drivers.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
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I am using the Microchip PIC18F2450 for USB communications. In fact, I am
making a device that will have a USB connection to the computer (and
possibly also a multiport USB hub), and it will communicate with another
PIC through a digital isolator using serial interface. This isolation may
be an important feature to implement in a cardiac device. I am not familiar
with the FTDI device, and I am sure the Microchip devices can do everything
it can do (except maybe the security dongle features). I will be completing
my design in the next couple of months. The second PIC is used for analog
data collection, so the OP's application has much similarity. I'm not an
expert at USB, but I do have the device working on Microchip's development
module. I'd be interested in learning more and helping if I can.

Paul



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