libftdi Archives

Subject: Re: LibFTDI read problem

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Wed, 21 Mar 2012 11:31:41 +0100
>>>>> "Daniel" == Daniel Scholz <ds1982@xxxxxx> writes:

    Daniel> Hey Guys, i have problems with my FT2232 with Linux.  I'm trying
    Daniel> to get my old Windows (here everything is OK) code working.
    Daniel> Simplest thing which doesn't work is setting the device in MPSSE
    Daniel> mode, sending a GET_BITS_LOW (0x81) and Read one byte.  With
    Daniel> Windows (and original ftdi d2xx driver) i get one byte back with
    Daniel> actual Pinstate. With Linux and libftdi readfunction always
    Daniel> returns number of read bytes zero.  Setting I/O pins with write
    Daniel> command (0x80) works without any problem.

    Daniel> Same with sending/receiving data with loopback (0x84) activated
    Daniel> or connecting any real device via spi or i2c.

Did you set the timeout to a short period? Did you try to terminate the
sequence with a "send immediate". Otherwise the FTDI may take a long time
until the chips decides to flush the few bytes in the buffer back to the
host.

Otherwise post a small example against the example directory so other can
have an easy look at the problem.

Bye
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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

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