Hello Ben, On Friday, 14. August 2009 22:49:05 Ben Plotnick wrote: > Without configuring the chip at all I see a ~16 ms delay on a read > command (I assume this is related to the timeout), which is out of spec > for my application. When I go to lower the chunk size and latency using > libftdi, I can set it and read it back, but then when I try to switch > back to VCP mode I get a /dev/ttyUSB0 not found error. I assume that > libftdi disables the VCP driver or something? > > I then cycled the power on the chip and was able to access ttyUSB0 again, > but the configuration reverted to the defaults. And I am guessing that > the configuration information is not stored on the EEPROM. So my > question boils down to this (assuming that I haven't totally misread the > documentation)... > > 1) How would I configure the chip and then proceed to use VCP?
That's exactly the reason why we started libftdi. Back in the days there was only the ftdi_sio kernel driver (you may call it VCP). It was very cumbersome to extend for non-standard featurs like bitbang mode or setting the latency. libftdi detaches the kernel driver. The latency setting and other values are configured "per session". I guess the chip reverts to the default settings once you close the interface. What about using libftdi instead of VCP for your application? Cheers, Thomas -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
