From: David Schleef Date: Sat, 1 Dec 2001 05:20:26 +0000 (+0000) Subject: Irrelevant, now that comedi_trig has been completely removed X-Git-Tag: r0_7_62~77 X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=7a5ce6820706e2185151974c612a89f0220ca123;p=comedi.git Irrelevant, now that comedi_trig has been completely removed --- diff --git a/Documentation/comedi/mode-info b/Documentation/comedi/mode-info deleted file mode 100644 index e9109ab0..00000000 --- a/Documentation/comedi/mode-info +++ /dev/null @@ -1,168 +0,0 @@ -From owner-comedi@stm.lbl.gov Tue Jun 29 00:56:15 1999 -Received: (from majordom@localhost) - by stm.lbl.gov (8.8.7/8.8.7) id AAA29747 - for comedi-list; Tue, 29 Jun 1999 00:56:15 -0700 -Received: (from ds@localhost) - by stm.lbl.gov (8.8.7/8.8.7) id AAA29742; - Tue, 29 Jun 1999 00:56:14 -0700 -Message-ID: <19990629005613.A29725@stm.lbl.gov> -Date: Tue, 29 Jun 1999 00:56:13 -0700 -From: David Schleef -To: Tomasz Motylewski -Cc: comedi@stm.lbl.gov -Subject: Re: pcl-711 driver ISR. -References: -Mime-Version: 1.0 -Content-Type: text/plain; charset=us-ascii -X-Mailer: Mutt 0.91.1 -In-Reply-To: ; from Tomasz Motylewski on Tue, Jun 29, 1999 at 02:22:26AM +0200 -Sender: owner-comedi@stm.lbl.gov -Precedence: bulk -Status: RO -Content-Length: 5035 -Lines: 143 - -On Tue, Jun 29, 1999 at 02:22:26AM +0200, Tomasz Motylewski wrote: -> -> Is there any documentation for _ai_mode0, 1 2 3 4 etc? Do they mean -> the same for different cards ? - -Found it. It has a little extra info, but that shouldn't hurt. -Here it is: - ------ -> -> 1. What are the different modes? 2, 3, and 4 seem pretty well -> explained, but I guess mode 0 is a one-shot sample, and mode is 1... -> what? - -0 is one-shot. Actually, some of the drivers will return as many -samples as you ask (i.e., trig.n), for the channels you specify. Others -will limit it to a reasonable number that will finish in 1-10 ms, and -the rest only return 1, for the first channel specified. The idea here -is "at the convenience of the driver, preferably fast." - -mode 1 is timed acquisition, with a single timer. For example, if -you request channels 2, 4, and 6, in mode 1, with the number of samples -(trig.n) = 2, and a timer value that corresponds to 100 us, the driver -programs the device to measure inputs at these times: - time chan - +0 us 2 - +100 us 4 - +200 6 - +300 2 - +400 4 - +500 6 -If you board can support mode 2, mode 1 is not necessary. Comedilib -will eventually emulate it. - -mode 2 is similar, but has 2 timers, a major timer (trig.timeval) -and a minor timer (trig.timeval1). Taking the previous example, but -with a major timer of 1000 us and a minor timer of 100 us, inputs -are measured at these times: - time chan - +0 us 2 - +100 us 4 - +200 6 - +1000 2 - +1100 4 - +1200 6 - -mode 3 is like mode 1, except that an external trigger is used. If -t(n) represents the time of the nth trigger, inputs are measured at -the following times: - time chan - t(1) 2 - t(2) 4 - t(3) 6 - t(4) 2 - t(5) 4 - t(6) 6 - -mode 4 uses an external trigger and a minor timer. With a minor -timer of 100 us, we get: - time chan - t(1) 2 - t(1)+100 us 4 - t(1)+200 us 6 - t(2) 2 - t(2)+100 us 4 - t(2)+200 us 6 - -As a bit of background, mode 2 & 4 are the most useful. Mode 1 -is the only supported by many boards. Mode 3 is the only supported -by a few boards. Mode 3 could be useful to synchronize multiple -boards, if the master board is capable of exporting a trigger signal. - -If you have an application that doesn't fit into the existing -modes, and your board supports it, I'm content with adding more -modes. - -> -> 2. How is the channel mask to be interpreted? If multiple channels are -> specified in the mask, should successive bytes in the data array match -> to different channels? - -CR_MASK() packs range, analog reference, and channel information into -a 32-bit integer. An array of these integers are passed from the program -to comedi, to be used as mentioned above. Samples are put into the -data array in time order. - -> -> 3. If ntrig is zero, does that mean sample nothing, or keep sampling -> forever? - -I haven't decided. Since comedi doesn't currently support continuous -acquisition, I have time to decide. It did previously, but I never -wrote buffer streaming code for the 0.6 series. It's on my list. -The alternative to specifying continuous is ((unsigned int)(-1)). - -> -> 4. How should a card like mine be handled, where there's a single A/D -> converter servicing multiple channels? Should the driver attempt to -> multiplex everything together, and then finally return an error if a -> request is made that just can't be squeezed in? - -If I understand what you are saying, yes. I.e., if in mode 2, you ask -for 10 channels, major timer 50 us, minor timer of 10 us, then yes, -you should return an error. In actuality, most drivers aren't that -mature yet. - -> -> 5. Anything else you can send me that's useful? I've got comedi and -> comedilib 0.7.0. - -Not really. I'm trying to pause comedi/comedilib development for -a little while so I can write documentation, so maybe soon there'll -be more info. - -Timer values are currently board dependent. Most boards use dividers -off a frequency like 20 Mhz, but some have multiple clocks and/or -prescalers. I'd like to just specify timers as (say) nanoseconds, -and let the boards do the division, but that limits timers to ~4.29 -seconds. - -About ranges, range info, range types, etc.: Typical boards allow -you to specify an input gain on the A/D converter, and possibly -also unipolar/bipolar. Collectively, these are "input ranges". A -board that allows 4 different gain settings, and unipolar/bipolar -setting, would have 8 available ranges, numbered 0-7. This range -specification is what you give to CR_PACK(). Not all boards are -identical, so each subdevice (or channel, sometimes) has a -range_type, to determine what voltages your range specification -cooresponds to. The low bits of range_type give the number -of ranges available. The high bits are used by the comedi module -when it is asked to return an array of comedi_krange structures; -these structures contain the max and min voltages and a unit -specification for each range. - - - - -dave... - - -**** -Sent by the Comedi mailing list - To unsubscribe, -send mail to with "unsubscribe" in the body. -