libftdi Archives

Subject: Re: libftdi vs d2xx behaviour - FT232r synchronous mode

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Wed, 25 Jan 2012 09:20:07 +0100
>>>>> "Lazarus" == Lazarus Longitudis <Lazarus-Long@xxxxxx> writes:

    Lazarus>  Hi,
 
    Lazarus>  I am trying to port some code from PyUSB with d2xx binary
    Lazarus> drivers from ftdi.  To get concrete it is this file:
    Lazarus> https://github.com/fizzisist/x6500-miner/blob/master/ft232r.py
 
    Lazarus>  I've replaced all calls. Now with the working read_data it
    Lazarus> looks quite good and it seems just straight forward.
 
    Lazarus>  Now I have some strange difference. On the first write/read
    Lazarus> cycle the original code writes and reads 306 bytes. The ported
    Lazarus> code write and reads 306 bytes too, but the first read 4 bytes
    Lazarus> differ in some bits.
 
    Lazarus>  The d2xx code returns: ['\x91', '!', '\xa1', '\xa1', '1', ...
 
    Lazarus>  The ported one: ['\x11', '1', '\xb1', '\xb1', '1', ....
 
    Lazarus>  There are no sticky bits nor one can says that all occurrences
    Lazarus> of i.e. 0x91 are read as 0x11.
 
If nothing else helps, try to debug the USB package with usbmon
(/usr/src/linux/Documentation/usb/usbmon.txt). I suspect however that there
was some mode switch before the output you cite that libftdi doesn't do
proper.

Bye
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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

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