Dumb device's USB to a DOS based PC's RS232. Does this interface exist?
Mickster
Posts: 2,694
Haven't found one using Google.
Mickster
Mickster
Comments
It seems like there's a growing number of microcontrollers capable of being a USB host. I'd think you'd use one of these uCs with whatever program would be required to make the protocol conversion.
Maybe the easiest way would be to use a RaspPi? A program would need to read from the USB device and then send the information over a serial connection (USB but this time to a USB slave). You could use either an USB (slave) to RS-232 serial converter or a RS-232 chip connected to the RaspPi's I/O pins to communicate with the DOS machine. (I think the RS-232 chip on the I/O pins would be too much bother.)
The problem is that the 'something' will need to be some sort of USB-master, and that typically means a computer of some sort.
Unless the device you have is very special, I'd rather look around for a model with an RS232 port...
end is just bare wires and outputs 5V serial, you can use your favorite connector. The cable works well and we have
1,000's of them in the field.
http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm
http://www.radioshack.com/product/index.jsp?productId=11024703
http://www.ftdichip.com/Products/Cables/USBRS232.htm
What are you actually trying to do?
you need something a lot 'smarter' to be able to connect an USBdevice to a PC's RS232 port.
Nice to see another South Bay Forumista with a Cessna!
erco/Torrance
PS: LA Robotics meeting this Saturday in Torrance, noon-3 or 4 pm. I'm showing a couple bots, FYI.
You just might find FreeDOS will do it.
http://www.freedos.org/technotes/newsitem/149.html
Thanks for all the responses, guys.
I know it's a long-shot and it would have to be something along the lines of what Duane suggests; a go-between intelligent converter of some description.
The problem is a failed 3M-Microtouch touchscreen. The DOS based code talks to it directly and it must be RS232, COM2, 9600, N, 7, 2. I wrote the code in the late eighties but no-longer have the source.
The owner of the system found a replacement touch-monitor and purchased it (no return possible) but it is the USB version and I was hoping that there was a bridging device to enable these to talk to each other.
I am amazed at the lack of available bridging devices in general. For example, BT devices can replace a RS232 cable but what about the same for USB? Granted, there would be a bandwith limitation but in some cases that's not an issue.
Mickster
It may be that the device IS serial, but has a FTDI or similar chip built-in as it may have been easier to update an old serial design with one, than have to create a completely new one...
If it shows up as a regular USB serial port, /dev/ttyUSB0 or such, and you can just send text and commands at it and receive whatever back then...
Get yourself a Raspberry Pi, connect the DOS box to it via USB serial. Plug the screen in. Write a little program in the language of your choice to shunt bytes between the interfaces.
Hide the Pi in the DOS box and hook it up to the PSU.
The problem with me getting involved is that he paid less for the touch monitor than my hourly rate and could probably find a RS232 model for a similar price.
Mickster
I don't know nothing about this device, but it's a USB host, does have a serial link to exchange data(perhaps) and I can bet someone here at the forums can explain a lot about its possible uses:
Parallax Memory Stick Datalogger #27937:
http://www.parallax.com/products/27937
It's based on one FTDI's Vinculum chipset.
This is the link for a thread where Mike Green posted something about its uses, perhaps he can add some more substance to my wonderings:
http://forums.parallax.com/showthread.php/149758-Is-it-possible-to-run-a-device-without-OS?highlight=vinculum
Hope it can help you a bit.
Yanomani
This does seem to be a blind spot. Asian vendors are moving to USB, and the other-choices are falling thru the cracks.
Microchip have a touch controller device, that can do USB or RS232, but you need to be lucky and have them use that.
For a while, keyboards would operate in either USB or PS/2 modes, just a simple physical adapter.
It's a no-brainer to have that same choice on a Touch interface, but sadly even that level is above mass-consumer engines.
There are plenty of choices of USB to RS232.
Touch bridge needs a custom USB-Host, programmed as ready to find a USB-Touch-slave, and turn it into a RS232 (or PS/2) interface.
I thought FTDI Vinculum-II had an application library for this, but I cannot find it now.
(perhaps it was too hard to support ? )
Have you checked what device(s) are used for the touch-USB - you might be lucky ?
I did find this :
http://www.actron.de/en/touch/touchcontroller_iframe.html#ERes458
which was the only one mentioning all 3 USB PS/2 RS232
I think using EETI S458XRUP
I haven't yet seen the USB touch-screen but I will take a run over there in the next few days.
I was hoping for an off-the-self solution because the following problems remain:
- If I get involved, I will have to charge him my going rate (more costly than purchasing another TS)
- I have no access to the source code of this DOS program so the raw data from the TS must be the exact same format.
Cheers!Mickster