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USB-serial converter with a USB-device connector

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

--
Urs Beeli  (discard the obvious to mail)
"Change is inevitable, except from a vending machine."
Reply to
Urs Beeli
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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

Reply to
Bob Stephens

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.

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Reply to
Mike Harrison

emulation drivers as well

specific to your

be able to use as a

Have a look at:

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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

RS-232 to VGA. Many resolutions http://www.dontronics.com/micro-vga.html
USB to RS232 Converter that works http://www.dontronics.com/usb_232.html
Reply to
Don McKenzie

emulation drivers as well

specific to your

be able to use as a

Bob, Mike and Don,

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

/urs

--
"Change is inevitable, except from a vending machine."
 -- Urs Beeli,
Reply to
Urs Beeli

port emulation drivers as well

software specific to your

you may be able to use as a

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

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PhilW

Reply to
Phil W

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.

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Reply to
picuser

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