Can't get FT232RL to work right?

Discussion in 'The Projects Forum' started by icydash, Aug 14, 2012.

  1. icydash

    Thread Starter Senior Member

    Jan 14, 2009
    Hey guys. I'm trying to make a USB --> UART interface and I can't seem to get it to work. I'm using the FT232RL IC as the interface. The datasheet for the FT232RL is here: Also in that folder is an image of the pin-out that I used, which I grabbed from the datasheet, to make the connections. My schematic is in the "FT232RL Connections" image, which is the schematic I've been using that I got from the datasheet.

    However, I have made the following changes when breadboarding the schematic from the actual schematic image on the website:
    1. I didn't use a ferrite bead. I was told I wouldn't really need it for my application and I could skip it by someone on these forums a long time ago (I don't remember who).
    2. for the 10nF capacitor, I didn't have a polarized one on hand, so I just used a non-polarized 10nF cap.
    3. I left out the 100nF and 4.7uF caps on the lower left-hand side of the diagram. I figured I can add these in later, but I think they're just for stabilization.

    Other than that, I'm pretty sure I have everything connected right.

    When I plug my USB cable into my computer, it recognizes that a USB device is attached, installs the software, and it looks like I'm good to go. However, when I open X-CTU, though it does show a USB Serial Port (Port 11), when I click the "Test/Query" button to try to communicate with the device, it always says "Unable to communicate with modem."

    Odd. Help please! =)