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Author Topic: FTDI Comunication Problem - Sometimes FTDI cannot be found  (Read 334 times)

yujiahei

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FTDI Comunication Problem - Sometimes FTDI cannot be found
« on: September 01, 2022, 07:37:31 AM »

Hallo,

i am working on a FPGA project and now facing a sporadic problem.

our project is about image capture device. we are using FTDI to transfer image data and command between device and host (computer). the ftdi is conneted to a on chip USB controller HUB. the FTDI is as self-powered mode configured. there are also some other chips connected with the on chip USB controller hub.

problem:
in the most time the system works good, but just sometimes, maybe in every 20-30 reconnecting, it can happen once, that the FTDI cannot be found in device manager (neither in USBview). the other chips which are also connected to the Hub are always ok, so I think the problem could by FTDI chip. So I mesured the critical pins value of FTDI like VBUS, WAKEUP, RESET and also the power supply for it. They are all correct.
From my side I think the reason could not be failed initialization of FTDI, because I didn't have to reboot the whole system but just reconnect it, then the FTDI appears again.
So I think, if it could be caused by unstable VBUS. But according to my mesurement there is no any glitch by VBUS when the problem happens.

Another weird point is that sometimes I can hear the correct beep, even when the issue happens. that means, we should have two chips registering in the device manager, and I can hear two times windows prompt tone when our device is being connected to pc, but I can not see the FTDI in device manager. And if when I focus on the USBView(a usb port tool), I am sure I can see somethings showing up on the port where the FTDI should be. But it disappers immeditaly.

at last I want to mention again, all these failures happen only randomly, around once in 20-30 reconnecting. most time it works fine.

I am looking forward for your help
Thanks a lot
YJH
« Last Edit: September 01, 2022, 09:19:54 AM by yujiahei »
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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #1 on: September 01, 2022, 01:18:53 PM »

Hello,

Which FTDI chip are using? have you got a schematic you can share? a USBView screenshot of the device would also be helpful. Also what kind of cable are you using to connect the FTDI device?

Best Regards

FTDI Community
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #2 on: September 01, 2022, 02:24:40 PM »

we are using FT601Q-B and the Cable is USB3.0 A to B. The relevante schematics and USBView screenshots are all in Attachments.

For your information, I also copied the USB info from usbview when the device works good. from the Timeview screenshots with name "Failed_1_UsbView.png" and "Failed_2_UsbView.png" you can find two failure situation.

by the way the driver is also the latest.

thanks
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #3 on: September 01, 2022, 02:26:20 PM »

sorry the attachments are too many. I have to upload them in two replies.
Thanks again.
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #4 on: September 02, 2022, 10:48:34 AM »

Update:

I tried to reset the ftdi from hardware side during running system, when the problem shows up. it can be fixed!
But I still don't understand why. Because if I don't reset it, but just reconnect it, I can also get the chip back in device manager.
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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #5 on: September 02, 2022, 03:22:30 PM »

Hi,

so it randomly disconnects and then once this happens it takes a few tries to get it to reconnect again? but using the device reset it appears again first time? am i understanding this correctly?

does the disconnect happen during any data transfer or can it happen even when the device is idle? you should have a look at the FT601 errata and see if any of the situations apply to you and let me know. TN_168 FT600/FT601 Errata Technical Note.

Best Regards
FTDI Community
« Last Edit: September 05, 2022, 04:18:04 PM by FTDI Community »
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #6 on: September 02, 2022, 03:29:45 PM »

Hi

it is not disconnected. it just doesn't appear sometimes in device manager. if this happens, i have to manuell disconnect the device and reconnect it, then i can get it back to device manager.
And today i found, i can also reset the ftdi chip to get it back appearing in device manager,  when it at first not appears
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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #7 on: September 05, 2022, 02:19:06 PM »

Hi,

it sounds like this could be a small hardware issue. do you experience this on any other PCs? Have a look at https://ftdichip.com/wp-content/uploads/2020/08/AN_430-FT60X-PCB-Layout-Guidelines.pdf. This goes over the PCB layout guidelines for FT601. It could be that your design is just on the cusp of working, and every once and a while it stops working and needs reset. I would go through the design guidelines to make sure everything is setup as it should be.

Best Regards

FTDI Community   
« Last Edit: September 05, 2022, 04:15:32 PM by FTDI Community »
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #8 on: September 05, 2022, 02:26:32 PM »

HI,

Thanks a lot for your helps. Just like you guess. It happens not by all of our devices, just some of them. but If the device has this issue, then it is no matter wicht PC you are using, it could also happen. So I also think this problem should be caused by our Hardware.

Best Regards
YJH
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yujiahei

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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #9 on: September 05, 2022, 02:47:01 PM »

Hi
By the way, the Link you shared, I cannot open it.
THX

YJH
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Re: FTDI Comunication Problem - Sometimes FTDI cannot be found
« Reply #10 on: September 05, 2022, 04:04:10 PM »

Hello,

Try this link AN_430 FT60X PCB Layout Guidelines. if that doesn't work you can find it on our website under application notes.

Best Regards
FTDI Community 
« Last Edit: September 05, 2022, 04:16:34 PM by FTDI Community »
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