USB -> RS-232 adaptors

[Andy]

NOTE: MP now sells their own USB to RS-232 adapter, specifically made for the Proteus! See here!


Disclaimer:

Not all USB->RS-232 adapters are created equal, and not all adaptors will work with the Proteus. I will do my best to help anyone who is having trouble getting their adapter to work, but please keep in mind that with all the different devices out there, it may not be possible to get the specific adaptor you have to work with the Proteus or Thoughtstream.

The information shown here is based around using the USB->RS-232 adapter with the Proteus, but the information is also applicable to using it with the Thoughtstream (or any other piece of hardware, really...).

Many of these adapters are very "generic" in appearance and do not have a model name or part number. It is only through careful examination and experimentation that the actual manufacturer can sometimes be determined. My example is for a USB->RS-232 adaptor that has no name other than Plug and Play USB to RS-232 written on it. It turned out to be a "Prolific PL2303" and that is where I found the driver for it. Many units out there come with terrible drivers and need to be updated from the manufacturer's web site. Determining which manufacturer built the device you have is sometimes a real challenge. The easiest way I've found is to install the driver that comes with the device, and then go to "Device Manager" (see instructions below) and see what Windows is calling it. Hopefully there is a model number which can be googled to find out the actual device manufacturer. From that, going to their web site usually results in finding an updated driver.

After you have determined the manufacturer and model number, and downloaded the latest driver, you just plug the device in, and after the usual "new hardware found" wizard, just select "install automatically" and it should be done.

The next step is to determine what com port the device has been installed to, and make sure it falls somewhere between 1-8. (The Proteus Editor only works with com ports 1-8)

After that, if you're using the Proteus, run the Proteus Editor software, and select the matching com port. On the Thoughtstream, run the Thoughtstream Interface software or Mental Games.

I have not had a problem running the com port at it's max. speed, but others have indicated that they have had issues. Perhaps make sure you are running the latest drivers for the USB->RS-232 adaptor, but if that doesn't help, lower the speed until it works. This may be one of the differences between some adaptors and others, their reliability at higher speeds.

Below are some screen shots.

Questions? Ask away!

[Andy]

Part 1: Installing the driver

First run the driver installer from the CD that came with your USB->Serial adaptor. Reboot the computer if prompted to do so.

Next, plug in the adaptor to your USB port.
You should get the "New Hardware Wizard" dialog.
Select "No, not at this time" and click "Next >"
Select "Install the software automatically" and click "Next >"
When the installation has completed, click "Finish"

[Andy]

Part 2: Finding out the manufacturer and model number

Image 1. Right Click on "My Computer" (Just "Computer" in Win7) and select "Manage"
Image 2. See Computer Management Window
Image 3. Click "Device Manager"
Image 4. Click on the "+" sign to the left of "Ports (COM & LPT)"
Image 4. Double Click the USB->Serial adaptor. It's named "Prolific USB-to-Serial Comm Port (COM4)" in my example, yours may have a different name and port number. In this case, you can see that the manufacturer is "Prolific". Write down this name.
Image 5. See the Properties dialog
Image 8. Click on the "Details" Tab at the top of the dialog, and then click on the drop down and select "Hardware IDs" Write down this model number string.

From all this, we have discovered that the manufacturer is "Prolific", and the model number is 2303. The model number is sometimes a little difficult to determine, but in this case, Pid is the "part number" and Rev is the firmware version.

Google the manufacturer name to find their website, and search for the updated drivers.

Download the driver for the specific model number of the adaptor you have and install it as described in Part 1.

[Andy]

Part 3: Finding out and changing the com port

Image 1. Right Click on "My Computer" and select "Manage"
Image 2. See Computer Management Window
Image 3. Click "Device Manager"
Image 4. Click on the "+" sign to the left of "Ports (COM & LPT)"
Image 4. Double Click the USB->Serial adaptor. It's named "Prolific USB-to-Serial Comm Port (COM4)" in my example, yours may have a different name and port number.

In this case, the com port is COM4, as seen in the name listed in image 4. If the number is anywhere from COM1 to COM8, you are fine. Write down that number and set the COM port in the Proteus editor to that same value.

Keep in mind that the COM port chosen by the driver MAY CHANGE depending on what USB port you connect it to or if other devices get connected. You can check the number anytime by following the steps above.

If the COM port is NOT 1-8, then follow the steps below.

Image 5. See the Properties dialog.
Image 6. Click the "Port Settings" tab at the top of the dialog, and then click "Advanced..."
Image 7. See the Advanced Settings dialog. Click the "COM port number" dropdown and select a number between 1 and 8. It is recommended that you don't select COM 1 or 2, as these are usually hardwired to ports on your motherboard, even if they do not have an external connector on your computer.

If the driver has selected a COM port number above 8 and you do not see the "COM port number" drop down, you have a device that may not work with the proteus. Make sure you have the latest driver. If you do, then you have an incompatible USB->Serial adaptor. Hopefully you can return it for a different one.

[Andy]

Part 4: SCREENSHOTS/IMAGES

[Andy]

Part 5: The rest of the screenshots...

[TheRock]

Hi Andy,

Another thing you can do while you are in the Advanced Settings is drag the slider on the Transmit Buffer to the SLOW end. (See attached jpg)

The "Change Data Transfer Rate" menu option in the Proteus Session Editor adjusts the rate at which the Session Editor program sends blocks of data to Windows operating system. From there the drivers take over. If all blocks were sent out of the USB port at the pace sent by the Session Editor all would work well. Unfortunately, a lot of USB2Serial drivers will queue up individual blocks of data until their buffer is full (or some latency time expires) then sends them all at once. This makes for efficient use of the timing frames used by USB protocol but wreaks havoc on the Proteus. Putting the slider in the SLOW position reduces the buffer size so USB2Serial has to send smaller packets.

Best regards,
TheRock

[Andy]

Thanks for the tip, Todd!

I might suggest though, that this only be done if you are having issues, as I have never needed to lower the speed on any PC or adaptor that I've installed so far with the Proteus. I'm sure I've just been lucky with the drivers so ymmv.

[Kat137]

Can I use a USB to mini 2.5 with the Proteus and Proteus Editor? The only "serial" port on my laptop is 9 pin female for a computer screen connection.

Or...do I use a DB9 male to 2.5 mini?

Confused, thanks in advance.

Kat

[Andy]

For the Proteus, you will need the black cable from MindPlace that has a 9-pin RS-232 Female connector on one end and a 3.5mm male "TRS" (headphone) connector on the other. (The Thoughtstream uses a grey cable from MindPlace and the 2 are not interchangeable)

There was no such cable that is USB to 3.5mm for the Proteus, but now there is! It is available from MindPlace here.

If the 9-pin end of the Black Proteus RS-232 to 3.5mm cable will connect to your PC, then you are golden, and you don't need a USB to RS-232 adapter.

If the connector on your PC were a 9-pin MALE then that would be an RS-232 connector. The female that you are looking at is probably a 15-pin if it's female and RGB for a PC monitor.

Most likely you need a USB to Serial (RS-232) adapter, and the DB9 female to 3.5mm TRS cable from Mindplace, which likely came with your Proteus.

Hopefully all that makes sense. Let me know if it doesn't!

-Andy.