Re: [Xc3sprog-users] speed...

[Uwe B. <bo...@el...>]

>>>>> "Jaap" == Jaap de Jong <jaa...@ne...> writes:

    Jaap> Hi Uwe Can you explain why it takes so long to read the bitfile?
    Jaap> The programming takes 935 ms while the whole procedure takes 3.9
    Jaap> s.  Well, it is no big deal, but I was just wondering...  Regards,
    Jaap> Jaap


    Jaap> time xc3sprog -c ftdi -v xyzzy.bit Release $Rev: 416 $ Free
    Jaap> software: If you contribute nothing, expect nothing!  Please
    Jaap> provide feedback on success/failure/enhancement requests!  Check
    Jaap> Sourceforge SVN for updates!  Using built-in device list JTAG
    Jaap> chainpos: 0 Device IDCODE = 0x01c2e093 Desc: XC3S1200E Created
    Jaap> from NCD file: xyzzy.ncd;HW_TIMEOUT=FALSE Target device:
    Jaap> 3s1200eft256 Created: 2009/02/16 15:15:04 Bitstream length:
    Jaap> 3841184 bits done. Programming time 935.8 ms USB transactions:
    Jaap> Write 244 read 7 retries 0 real 0m 3.90s user 0m 2.85s sys 0m
    Jaap> 0.06s

(forwarded to xc3sprog-users)

Jaap, what was you setup? I guess it was a FT2232D|L linked directly into
the PC. That way, the Full Spped devices is handled as full speed device in
the PC, and transaction take place in one millisecond steps. If you connect
the FT2232D|L to a USB-2.0 hub, as written in the README, the hub stores and
forwards microframes and things happen in 125 Mikrosecond steps, in the best
case a 8 Times enhancement.

The FT2232H will work that fast without the HUB, as it is a high speed
devices per se.

Bye
-- 
Uwe Bonnes                bo...@el...

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
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