USB-serial converter with a USB-device connector

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We are currently redesigning one of our machines that only has RS-232
interfaces and out marketing wants us to support USB as an interface. The
redesigned interface board will contain an USB device interface but will not
be available soon enough for the suits :-)

So as an iterim solution we are looking into ways to make our old product
'speak USB' at little cost. What we are thinking about is to use an
USB-RS232 converter, so at least people can hook up to our machine with a
USB interface although still use a virtual COM port.

However, the plethora of converters on the market seem to aim at the PC end
of the problem and all come with 'USB host' connectors (USB A). What we
would need is such a converter with a 'USB device' connector (USB B) in
order for our product to offer the correct plug so it can easily be
connected to a PC using a normal USB A-B cable.

Are there such beasts? If anyone can point me in the right direction I would
really appreciate that.


We are also considering the alternative of 'doing it ourselves' instead of
buying a finished product. Obviously we would want to use a single-chip
solution that fully integrates the conversion and ideally also comes with
windows drivers to emulate the COM port.

Does anyone know of such chips that you can recommend? Controllers with USB
ports that require programming are not an option as that would mean to much
implementation effort for us to be worth it.

Thanks for your help.

Best regards
/urs


--
"Change is inevitable, except from a vending machine."

Re: USB-serial converter with a USB-device connector

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Check out the PIC18F4550 from Microchip or the Silicon Labs CP2101, both
are designed to work with virtual UARTS mapping COM ports to USB.

TANSTAAFL however.

Bob


Re: USB-serial converter with a USB-device connector
On Fri, 3 Jun 2005 13:01:38 +0000 (UTC), Urs Beeli

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The FTDI FT232BM chip is widely used and works well. They supply COM port
emulation drivers as well
as native mode drivers that allow better control if you're writing software
specific to your
application.

They do a DIL module containing the chip and a USB B connector which you may be
able to use as a
quick fix for your product - look for DLP-USB232M on their website.

http://www.ftdichip.com/Products/EvaluationKits/DIPModules.htm


Re: USB-serial converter with a USB-device connector
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emulation drivers as well
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specific to your
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be able to use as a
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Have a look at:
http://www.dontronics.com/cat_index_hard.html#usb
for a large range of USB devices that may help solve your problem.

Don...



--
Don McKenzie
E-Mail Contact Page:       http://www.e-dotcom.com/ecp.php?un=Dontronics

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Re: USB-serial converter with a USB-device connector
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emulation drivers as well
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specific to your
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be able to use as a
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Bob, Mike and Don,

Thanks for your suggestions. Exactly what we have been looking for.

/urs


--
"Change is inevitable, except from a vending machine."

Re: USB-serial converter with a USB-device connector

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port emulation drivers as well
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software specific to your
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you may be able to use as a
Quoted text here. Click to load it

FTDI chip sets are ok if you only use standard coms.
However, they do not fully replicate a PC serial port.
On a standard PC serial port you can manipulate the Mark/Space parity to
implement a 9 bit protocol. The FTDI chipsets do not support this parity
manipulation.

There are other chipsets around which do.

We use a protocol that relies on 9 bit format and we have it communicate
with a standard PC serial port. With the increasing demise of standard
serial ports the use of a USB dongle was hoped for. Currently however most
do not work, since they do not fully replicate a standard serial port. There
are some that do but finding a reliable source can be tough.

We find a very good solution with a single chip that fully supports a
standard serial port. No xtals etc just the chip to handle all the USB and
serial I/O. It does need a TTL to RS232 level translation chip, but that's
all. And it's cheap.

Devices are CP2102-GM or the CP2103-GM and are manufactured by Silicon
Laboratories.

Their web site is
http://www2.silabs.com/tgwWebApp/public/web_content/products/Microcontrollers/Interface/en/interface.htm

PhilW




Re: USB-serial converter with a USB-device connector
The HR-USBUART is an excellent USB to UART converter - it is tiny (only
8 pins DIL) with the mini-B connector. The drivers work great too -
never had a problem with it.

http://www.customidea.com/hr-usbuart.php


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