libftdi Archives

Subject: Test Programs, Was Re: FT2232H/MPSSE/JTAG Device Freeze

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Tue, 29 Sep 2009 21:07:42 +0200
>>>>> "Matthias" == Matthias Janke <janke@xxxxxxxxxxxxxxxxxxxxxxx> writes:

    >> The only problem: Sometimes the FTDI chip does not send any data when
    >> it should send something - causing my application to freeze. In this
    >> situations it seams like the chip ignores all the data I send to it.
    >> 
    >> Usually this happens when I invoke my tool a 2nd time after it has
    >> been finished with the first call. Which brought me to the theory
    >> that something is wrong with my setup/cleanup procedures...
    >> 
    >> The only way to make it working again is to disconnect and reconnect
    >> the device...
    >> 

    Matthias>  I have similar problems in serial mode with a FT232R. To
    Matthias> reset the device without repluging it I used the code from
    Matthias> here:
    Matthias> http://marc.info/?l=linux-usb-users&m=116827193506484&w=2
    Matthias> Another option to reenable the device without reset is to open
    Matthias> and close the device with FTDIs D2XX driver. I tried to dig
    Matthias> into it with usbmon and wireshark, but they never returned any
    Matthias> send data, so I gave up.  HTH
 
  echo 1 > /sys/module/usbcore/parameters/usbfs_snoop

might be of help

I can confirme the problems with libftdi application hanging. While hunting
the 0x4b TMS bug with 7 bits of tms, I wrote a test application with
libftdi. It was more then flaky. Then I rewrote for ftd2xx and things run
smooth.

For reference I have appended both source. 

If people could try out and tell there findings. I am gratefull.

Run with "-t 6" e.g. to see expected behaviour. "-t 7" is default and show
how the TDI/DO bit is shifted out TMS on the last edge of the last TCK
clock..


Bye
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------


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