Daqarta for DOS Contents



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Daqarta for DOS
Data AcQuisition And Real-Time Analysis
Shareware for Legacy Systems
(Use Daqarta for Windows with modern systems)

From the Daqarta for DOS Help system:



This driver allows you to specify certain parameters on the STIM3A.GEN line, which must be located anywhere past the 4th line of the DQA.CFG file. Each parameter is given as a letter and colon, followed immediately by a value. Use one or more spaces to separate parameters. For example:
    STIM3A.GEN  B:64  R:1  S:+MYSETUP.S3A
The order of the parameters is not important. None of these parameters is required; they are all optional.


When STIM3A loads, it looks for an SB16 or ATN-SB16 module with attenuators it can control. If it finds one, it sets the Output dB control to work together with that attenuator, and locks the SB16 or ATN-SB16 controls to display-only. If not, it defaults to a 0 to -6 dB range, allowing any other attenuator to be used manually.

You can still get 0.01 dB resolution with such a manual attenuator, though it's more cumbersome: You need to set the manual attenuator to the next-higher output level it can reach, then set Output dB to make up the difference.

If for some reason you want to use an SB16 or ATN-SB16 in this independent mode, change DQA.CFG to include:

    STIM3A.GEN  A:2
Normally, when you start STIM3A or load a new setup file, the Output dB controls are forced to 'Mute' regardless of the values stored in the setup. This is intended to prevent an unexpected blast of sound. However, if you don't need this safety measure you can use:
    STIM3A.GEN  A:1
Then when you load a setup, either manually or via the startup S: parameter, the Output dB values will be as stored. This is handy if you want to change to various setups with particular levels.


Longer stimulus memory buffers allow longer stimuli in Sequential mode, or longer cycles in Static RTime mode. The default buffer size is 16 Kbytes, which is all that is needed for Dynamic RTime mode. To change the buffer size, change the invocation line in DQA.CFG to read:
    STIM3A.GEN  B:n
where n is a number from 16 to 64 representing memory Buffer size in Kbytes.

Alternatively, you may specify the buffer size using the same B:n notation on the INIT (first) line of DQA.CFG. This is intended for use with boards like the Sound Blaster SB16/32/64 that can use DMA for both input and output. Since DMA accesses must never cross an absolute 64K memory boundary, Daqarta will take care of the alignment without wasting any memory. It does this by juggling the locations of several program segments to get an optimum fit, but it must do this before any modules are loaded... thus, the INIT line at the start of the configuration.


For Sequential modes or Static RTime mode, the maximum number of time samples (ie. a sample each from all active outputs) versus buffer size in Kbytes is shown in the following table. There are no limits in Dynamic RTime mode.
 Memory Buffer size:           16K     32K     64K

                             ----- Time samples ----

 One DAC, 8-bit:              16384   32768   65536
 One DAC, 16-bit:              8192   16384   32768

 Both DACs, 8-bit:             8192   16384   32768
 Both DACs, 16-bit:            4096    8192   16384

 Digital only:                16384   32768   65536

 8-bit DAC + DigOut:           8192   16384   32768
 16-bit DAC + DigOut:          5461   10922   21844

 2 x 8-bit DACs + DigOut:      5461   10922   21844
 2 x 16-bit DACs + DigOut:     3276    6552   13104


This driver normally attempts to load this associated Help file on start-up, and exits with an error message if it can't find it. Setting F:0 on the STIM3A configuration line tells the driver not to look for the file. You would probably only want to use this option if you are really short of DOS memory, since loading the Help file only increases memory use by a few hundred bytes for its separate link stack and directory. (The file itself shares the text buffer of the Main Help file.)

Note that ALL Help files, including main, can be omitted via an F:0 parameter on the INIT line (first line) of the DQA.CFG file. If this is present, no individual module Help will be loaded.


By default, STIM3A starts the random generators with the same random seeds for each session. That means that although within a session all values are random, the overall session can be repeated exactly. If you use R:1 on the STIM3A.GEN configuration line, the random generators will be started with seeds that differ each time, based upon the time, date, and various internal states.

In many instances there is no need for this, since there will be session-to-session variations due to human interactions. For example, the time between turning on a noise source and starting some operation that uses it will differ between sessions, if you perform the operation manually (as opposed to using a Key Macro). Since the random generator keeps running during this interval, it will typically be at a very unpredictable state by the time the operation starts.

But if you have a standard test series which you run from a setup file and Key Macros, there might be no variations between sessions. If you wanted each session to be random, use the R:1 parameter.

Another consideration is setups that use multiple random generators, where you want to be sure that they do not always start with the same relation to each other.


A setup file can be loaded automatically at the start of each session by means of the S: parameter on the STIM3A.GEN line of the DQA.CFG file. This setup can be one that you have created via the Save Setup option, or from the Quit prompt at the end of a session where the setup has changed, or it can be a setup that was created on another system.

There are three different options for this parameter:

   S:+                  ;Loads the default SETUP.S3A file.

   S:+FILENAME.EXT      ;Loads FILENAME.EXT instead.

   S:FILENAME.EXT       ;Sets the default Load name/path only.
This last option doesn't actually load anything, but it changes the default Load Setup file name and path from '*.S3A' to whatever you want. You would typically use this if you preferred to use an extension other than .S3A, or if you wanted to keep all your setup files in some other directory than the default directory that Daqarta resides in.

Note that while you may load setups from any directory, any Arb and/or Play files included in the setup are assumed to reside in the default directory.

When you auto-load a Setup file at start-up, the Master output control is forced Off. This is a safety feature to prevent unintended actions. Just toggle it on normally whenever you want output. If you really want immediate output on start-up, use the Auto-Initialization Key Macro to toggle Master on.

This safety interlock is not present when you load a Setup file "manually" with the Load Setup options, since in that case the system is always in Pause mode after loading. If Master was active when you originally saved the Setup, then just unPause to start the output.


By default, the Output dB controls operate like ordinary "volume" or "level" controls, where "up" always gives greater output. Maximum output is at 0 dB, and all other values are negative relative to that. When you start at the default 'Mute' (maximum attenuation) state, you scroll up to get more output. Output dB then goes from maximum negative to less- negative values toward 0.

Some users prefer "up" to actually increase the attenuation, as would be the case with some manual attenuators. You can tell Daqarta to use that convention via the U:1 parameter:

    STIM3A.GEN    U:1
With this option the maximum output is still 0 dB, but now you must scroll DOWN to get to there from the starting 'Mute' state. Attenuation is shown in positive dB.

This is simply a matter of personal preference.

Note that for direct entry, you never need to include a minus sign... it will be ignored if you do, regardless of which option has been chosen.


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