Can't get FT232RL to work right?

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

  1. icydash

    Thread Starter Active Member

    Jan 14, 2009
    81
    0
    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: http://www.quickid.net/usbDox/. 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! =)
     
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