>>>>> "Joerg" == Joerg Wunsch <libftdi@xxxxxxxxxxxxxxxxx> writes:
...
Joerg> However, it experienced funny performance effects. Attaching the
Joerg> UM232H module to a fullspeed (only) hub results in a huge
Joerg> performance degradation. Reading a 128 KiB controller takes
Joerg> about 50 s, while an FT2232D-based board on the same hub, same
Joerg> libftdi, same libusb takes between 10 and 12 s (depending on the
Joerg> bitbang clock speed).
Joerg> Plugging that UM232H into a highspeed hub gets it to fancy 5 s.
...
Okay, I now have a MEGA18 test board, with 12 MHz crystal and clock fuses
enabled, so I see the oscillation on the crystal with the scope.
Programmer is a FT2232H board with buffers and 33 Ohm series resistor.
Reading
./avrdude -C ./avrdude.conf -c ftdijtag -p m16 -b 2000000 -U flash:r:test:i
takes about 0.45 sec versus 1.75 sec with USB2 disabled on the system.
This doesn't seem strange to me, no factor 10 as you see.
Can you reproduce the strange results with an FT2232H or does it only happen
with the FT232H?
--
Uwe Bonnes bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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