- From: Frank Mori Hess <fmhess_at_users.sourceforge.net>
- Date: Thu, 8 Aug 2002 18:40:40 -0600
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Thursday 08 August 2002 16:44, you wrote: > However, if I disable channel 1 in software, the interference pattern > disappears. > > ***Even though channel 1 is still physically connected to its signal > source**. > > Basically, the simple act of issuing a comedi_data_read() on channel 1 > affects/modifies the waveform I get out of channel 2. > > Is this odd or what? It is how the software is currently designed to work. > > At first I thought that maybe this was because my two comedi_data_read()s > were issued one after another, and I was hitting some limit on how fast > you can talk to this board. However, introducing some usleeps in the two > successive comedi_data_read()s for the two channels doesn't help matters, > so it isn't the fact that the comedi_data_read()s were happening one after > the other.... Yes, the multiplexer is not changed until you call comedi_data_read() and there is no settling delay between setting the multiplexer and starting the conversion. comedi_data_read_hint() can be called to set the multiplexer before you do your usleep, or comedi_data_read_delayed() will delay for the specified amount between setting the multiplexer and doing a conversion. - -- Frank -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE9Uw+L5vihyNWuA4URAmC5AKDkLBgLpYe8j7ZX48/9E8w/RIxGeACg5u9f upCbljI70l45xbWawCnmB/k= =PPQD -----END PGP SIGNATURE-----
Received on 2002-08-08Z23:40:40