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Subject: Re: [libftdi 0.18] SPI with CBUS Bit-banging FT232H

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Tue, 5 Jul 2011 10:54:00 +0200
>>>>> "Alex" == Alex Stefan <alexandru.stefan@xxxxxxxxxxx> writes:

    Alex> On 7/4/2011 7:54 PM, Uwe Bonnes wrote:
    Alex> I should have been more specific. I was refering to ideas on how I
    Alex> can improve the USB timing.

Queue as much as possible in one request. Read as large as possible chunks.

Be sure the FT232H gets recognized as a USB-2.0 device on your PC. If you PC
setup isn't right and the device is only connected to a " Linux Foundation
1.1 root hub" as seen with lsusb, only 1 mS frames will be used as opposed
125 us microframes on a 2.0 hub.

B.t.w. with the older  FT2232D devices, it helped to connect a USB-2.0
external hub between the device and the root hub. The hub was forcing Linux
to use microframe to the USB-2.0 full-speed FT2232D, while directly
connected only normal 1 ms frames were used.

Bye
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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

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