- From: (unknown charset) Lorenzo Dozio <dozio_at_aero.polimi.it>
- Date: Wed, 12 Mar 2003 09:55:19 +0100
Frank Mori Hess wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On Tuesday 11 March 2003 05:47 am, Lorenzo Dozio wrote: > >>Hi, >> >>I'm working on an industrial project using RTAI-Lab with Comedi support >>to manage analog I/O of a ComputerBoards PCI-DAS 1002. I noticed that >>the driver (cb_pcidas) misses a waiting time for multiplexer to settle. >>This lack involves wrong readings with multiple consecutive >>comedi_data_read calls on different AI channels. You can test the >>outcome simply by adding other comedi_data_read to the "inp" demo under >>Comedilib. >>The right behaviour is retrieved by adding a delay of 5 us after the >>writing to the ADC Channel MUX and Control Register. >> >> > > It's not a bug. Use comedi_data_read_hint() or comedi_data_read_delayed() to > allow the mux to settle. > So other drivers are buggy because they insert udelay to allow the mux to settle (e.g das08.c, cb_pcimdas.c)... Moreover the functions you cite are not available in kcomedilib... There is no unified approach about this point. Ciao, Lorenzo.
Received on 2003-03-12Z08:55:19