Help with FTDI

mynet43

I have a Propeller board talking to a PC through a USB cable, using the FT232RL chip.

I'm using FullDuplexSerialPlus on the Propeller side and RobotBasic on the PC side. I'm running at 115200 baud. They send text messages back and forth to control operation.

Here's my problem. I've run this connected to 5 different PC's: three with Windows XP and two with Windows Vista. On every one of these, the programs work perfectly.

I recently tried it with two other laptops PC's, each running Windows XP. On these, the USB interface doesn't work correctly. Whatever is sent out from the PC is returned back to the PC when it asks for serial input. It's like there was a loopback cable connected, but there's not. It's the same USB cable that works fine on the other PC's.

Does anyone have any idea why these laptops won't communicate the same way as the 5 that work fine?

Thanks for the help. Right now I'm stumped.

Jim

Mike Green

Try reinstalling the FTDI drivers on the PCs that don't work properly. I don't know what program you're using to communicate to the Prop, but try reinstalling that as well on those machines. I'm not aware of an option in the driver that would cause the echo, but many terminal programs have such an option for situations where the terminal device doesn't provide its own echo. Such an option might be erroneously enabled.

mynet43

Hi Mike,

Thanks for the quick response.

The two laptops that don't work asked for an FTDI driver, so I installed the latest one, 2.06, from the web site. The other 5 PC's that work are each using an older FTDI driver, 2.04.16. I don't know if this is related to the problem, but I asked FTDI to send me the install for the older driver. That should arrive by email later today.

The program I'm using to communicate the the Prop from the PC is RobotBasic. It works perfectly on all 5 of the systems that work. I'm using a compiled .exe file on the PC.

Do you know if there is any setting on the PC that would make it do an internal loopback?

Thanks for the help!

Jim

Mike Green

I'm really a poor person to ask about Windows. I mostly use a Mac and, when I have to use Windows, it's XP under a virtualizer (Parallels Desktop) under the MacOS and all that hides some of the device related "odd stuff".