Re: Merely discovering FTDI devices using libftdi/libusb detaches them from ftdi_sio

[Paul Ourada <paul@xxxxxxxxxxxxxxxxxxx>]

Thanks so much, Eric, Joe and Uwe. I had a suspicion that this might be the case. This exercise is to reduce the time spent attaching serial devices, and setting jumpers on the UART board to configure the serial comm type when deploying dozens of systems using these devices. We manufacture (for private corporate use) boards that use these FT4232H devices, and your suggestions would minorly complicate the build process, but such a change would only require setting the eeprom once. So the tradeoff may be acceptable to mgmt.

At present, I'm using the libftdi C API to open a particular device at a particular bus address. I think I may have mentioned that the Raspberry Pi seems to enumerate the bus in the order of the hub connections. We just put the port controller FT4232H device in the last slot. Of course, if someone should unplug and replug this device, then the enumeration is updated and things don't work until reset.

Again, thanks for your suggestions!

Best Regards,

Paul 

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From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Sent: Tuesday, June 5, 2018 4:28:15 AM
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Subject: Re: Merely discovering FTDI devices using libftdi/libusb detaches them from ftdi_sio

 

>>>>> "Joe" == Joe Zbiciak <intvnut@xxxxxxxxx> writes:

    Joe> I echo Eric's suggestion.  On my devices, I personally set the
    Joe> manufacturer string, description string, and serial number in
    Joe> EEPROM to something I can use to directly identify my device.  I
    Joe> don't generally change VID/PID, so I can use whatever stock FTDI
    Joe> driver is installed in the computer I plug into.

    Joe> I don't remember offhand, but do you also need to set the
    Joe> CHANNEL_x_DRIVER fields in EEPROM to indicate you want bitbang
    Joe> rather than VCP, or does that only affect non-Linux platforms?

Look at DS_FT2232H datasheet "4.13.1 Do I need an EEPROM?"

Bye

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Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 1623569 ------- Fax. 06151 1623305 ---------

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