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Author Topic: FT4222 cannot set speed. Exception raised  (Read 286 times)


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FT4222 cannot set speed. Exception raised
« on: November 05, 2021, 01:48:35 PM »

Using the FT4222 to communicate with MCU over SPI.

Same hardware and software has worked flawlessly in many instances.

However we are trying out a touchscreen integrated with PC.  Touchwu TD101E.
When FT4222_SetClock is executed it throws exception.

Code: [Select]
            ftStatus = FT_OpenEx(devInfo.LocId, FT_OPEN_BY_LOCATION, ref ftHandle);

            if (ftStatus != FTDI.FT_STATUS.FT_OK)               //  not true.   Status is OK
                StringAppendRTB("Open NG: {0}" + ftStatus);

            // Set FT4222 clock
            FT4222_ClockRate ft4222_Clock = FT4222_ClockRate.SYS_CLK_24;

            if (ftHandle == null) MessageBox.Show("NULL");


                ft42Status = FT4222_SetClock(ftHandle, ft4222_Clock);   // here throws exception


                MessageBox.Show(" cannot set USB clock " + ft42Status.ToString());    // status here is OK

I am sure this is related to the new touchscreen PC but I don't know where to look in the specs to prove it.

We have updated all the chip drivers per the manufactures supported drivers.

Why would set clock throw an exception?



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Re: FT4222 cannot set speed. Exception raised
« Reply #1 on: November 05, 2021, 04:01:20 PM »


You should try running our FT4222H code examples to see if it really is the PC. LibFT4222 Windows Library (v1.4.4) and Examples.

Also, i will need to know more about the exception. feel free to email with the details: support4@ftdichip.com

Best Regards

FTDI community