FTDI FT232R Question

Timothy D. Swieter

I am designing a product using the Propeller and the FT232R.· The USB Port is mainly used for development of the product by downloading firmware and receiving debug data back.· The first revision of the product will probably not implement the USB for anything more than a firmware updater.· Future version of the product will use the USB as a means to control the device from a com port and a Windows application.

My question stems from an annoyance.· With each prototype device I plug into my USB ports a new Windows com port is allocated.· Is there a way to configure the FTDI driver to only allow certain com ports?· Is there a way to remove unused com ports?··I am juggling two prototypes. I only have·one plugged in at a time.· Eachtime I switch·which one is plugged in I need to restart·Hyperterminal with a different com port address.· My device was not going to implement the unique identifier in USB since it needs nothing more than a com port and the device is for a limited market anyway.

Any advice or pointers is appreciated.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter
tdswieter.com

---

One little spark of imagination is all it takes for an idea to explode

Phil Pilgrim (PhiPi)

Timothy,

I feel your pain. There are two things you can do:

1) Alter how the driver assigns COM ports, so the port number is attached to the USB port, not to the attached device. This option is painful, involving changes to the FTDI installation script, as well as to the Windows registry. The FTDI website should have an appnote for this. Unfortunately, there's no way to script it, since each computer is unique, and you have to dig for hardware USB port info using a program from Microsoft.

2) Use the FTDI-supplied program MPROG to reprogram the serial numbers of your FT232Rs so they're all the same. That way one device will look like any other when attached to your computer, and they'll all be assigned the same port. ('Don't know what happens if two are plugged in at once, though.)

-Phil

Timothy D. Swieter

Thank you Phil. I will look into option 2 because that sounds like the least painful for now. I will experiment with what happens when the two chips with the same serial number are plugged in at the same time.

Thank you again.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter
tdswieter.com

---

One little spark of imagination is all it takes for an idea to explode

uxorious

You can also try the FTClean utility from FTDI to remove all instances of the com ports from the registry. We ran into a problem downloading firmware into Crossbow's Telos Motes that use the FTDI chip during preproduction runs. Since windows assigned each new mote a new com port and the download program only recognized up to com port 255, we could only program 255 units. We ran the FTClean utility and then reloaded drivers. Then the system started assigning com ports at com 3 and went up again. (the PC had com 1 and 2 onboard) Fortunately we have changed to downloaded the firmware via JTAG.

http://www.ftdichip.com/Resources/Utilities.htm

on a side note, Crossbow's Telos Mote uses the same temp/humidity sensor that Parallax does.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
~~ dRu ~~

crgwbr

I definitely feel your pain bro. Right now, my system has 30+ com's assigned all to FT232Rs. The serial number change sounds like a good idea. I'll try it and let u know how it goes.

Regards,
Craig

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"... one of the main causes of the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs." -

"If Python is executable pseudocode, then perl is executable line noise."

"The best accelerator available for a Mac is one that causes it to go at 9.81 m/s2."

"My software never has bugs. It just develops random features."

"Windows isn't a virus, viruses do something."

"Programmers are tools for converting caffeine into code."

"Enter any 11-digit prime number to continue."