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Daqarta for DOS Data AcQuisition And Real-Time Analysis Shareware for Legacy Systems

From the Daqarta for DOS Help system:

KEYBOARD RESPONSE CONTROL:

Keyboard Response Control Menu
Cursor "Run" Response (IntCr)
"Sticky" Shift Keys
Cursor Exchange
Keyboard Control Utility

KEYBOARD RESPONSE CONTROL MENU:

CTRL-K brings up a menu to help you adjust the "ballistics" or "feel" of cursor motions. The best settings are highly dependent upon your own personal preferences, as well as the performance of your system and the nature of the particular task you are doing at the moment. If you find that you need to alternate between tasks that are easier with different settings, consider using the Key Macro system to reset all the parameters automatically as a part of the task change.

The menu options are:

Hardware Delay:

This is the delay between the time you push down a key and the time your keyboard's built-in automatic repeat function kicks in. High values mean more initial hesitation when you want to move the cursor, which could be annoying. On the other hand, too little delay could mean unintended overshoot when you are just trying to nudge the cursor.

There are four settings available from the standard AT keyboard controller chip: 250, 500, 750, and 1000 msec. XTs have only a fixed value of about 500 msec.

Hardware Rate:

Once a key has been held down for the Hardware Delay time, the keyboard controller starts pumping out repeats of the keystroke at this rate, in characters per second. A high rate gives fast response, but makes it much easier to shoot past your target.

There are 32 settings available from the standard AT keyboard controller chip, from 2.0 to 30.0 characters per second, with finer steps at the low end. XTs have a fixed rate of about 10 characters per second.

Although AT-class machines allow the delay and rate to be programmed, the controller chip has no provision to allow reading the initial values. This means there is no direct way to restore your original settings automatically upon exit from Daqarta. If you find that the settings you want for Daqarta are different from those you want for other programs, consider invoking Daqarta from a batch file that runs the XKBD.EXE utility afterward to set whatever values you prefer. If you have DOS 5 or later, you can use the MODE CON command provided by DOS instead. Alternatively, you could program the settings into a Key Macro and execute it just before you Quit.

Cursor Max Step:

Daqarta cursor motions have a dynamic response: The longer you hold the cursor key down, the bigger the steps the cursor takes on each auto-repeat, up to a limit set by this Max Step value.

Cursor Rate:

This sets the cursor acceleration rate, or how fast the cursor step size approaches the Max Step limit, from 0 (constant step size) to 15 (super-fast acceleration).

Cursor Fixed Step:

If you hold down the SHIFT key when you while hitting a cursor arrow key you will get fixed steps of this size instead of the above dynamic cursor action. If you have set the dynamics to be best for fine tuning (low Rate, low Max Step), the fixed step can be set to a large value to allow rapid motion to a new area. Conversely, if you set the dynamics for big steps and rapid acceleration, you can set the fixed step to a small value to aid in fine tuning.

Note that dynamic and fixed cursor action work with menu value scrolling adjustment as well as trace cursor motion.

The Fixed Step option is also very useful with Key Macros to allow convenient parameter steps.

Readout Avg:

To keep the trace cursor readouts from becoming too much of a blur with noisy data, continuous running averages are performed on the Y-values before display. The Readout Avg value is a time-constant that indicates the maximum number of values that will be averaged. Larger settings give slower response times, so that while the display is easier to read, it may lag behind sudden changes in the signal.

The semicolon key or the number pad 5-key will force the averages of both cursors to immediately reset to their respective instantaneous values. Similarly, whenever you move an individual cursor, its average is reset. This is important when you have the Readout Avg set to a high value for viewing very noisy data, but there are occasional level changes. Since the instantaneous value is usually closer to the final average than was the prior value, the time for the readout to settle is much faster than waiting for it to slowly grow or decay between levels.

If you have one cursor set to a baseline portion of a waveform, and the other set to a particular peak or other feature, you may want to reset just the feature cursor average if only that portion changes. To do this, just nudge that cursor over one point and back.

You can easily experiment with readout averaging using the Virtual Source. Increase Noise to see the benefits of readout averaging. Virtual Source changes normally reset the readout averager automatically to speed settling time, but if you use SHIFT-Up/Dn to change values this will be omitted. This allows you to change Level and see the effect of a step change on the cursor readouts, as though the step came from a "real" external source, and you can also see the effects of cursor motion or the reset keys.

CURSOR "RUN" RESPONSE (IntCr):

If you hold down a cursor key, it will generate a series of key repeat interrupts at the Hardware Rate. By default, Daqarta typically tries to update the trace after each of these. But at high cursor repeat rates, or with slower processors, there may not be time to complete the update before the next key interrupt arrives, and the cursor response may appear to be slower than the selected Hardware Rate.

In this case, you can select IntCr with SHIFT-I, and the held cursor interrupts will have priority over the trace updates. The trace will momentarily "freeze" while you scroll the cursor, then resume updates as soon as you release the key.

This option is the start-up default for 286 and slower CPUs (PCs and XTs).

"STICKY" SHIFT KEYS:

The Scroll Lock key toggles a "sticky" shift state, allowing one-hand operation. Hitting SHIFT, CTRL, or ALT while this is active will bring up the usual shifted option key display at the bottom of the screen, but it won't go away when you release the key. Instead, it will remain active and that state will apply to the next key you hit. If you hold that key down, as in moving the ALT trace cursor, the shift state will remain in effect until you release it.

If you inadvertently hit an unintended shift key while in this mode, you can remove the "stuck" shift state by hitting that shift key again.

When you are entering text, such as for the comment line, there is no change to the option key display to indicate when you have hit the SHIFT key to capitalize or the ALT key for special characters (ALT-u for µ or ALT-2 for ²) or ALT-DEL to delete to the end of the line.

The sticky shift feature is intended to make life easier for those with disabilities... which includes anyone with one hand occupied holding a probe onto a circuit board, or opening an infusion stopcock, or any similar real-world situation where you need to do two things at once.

CURSOR EXCHANGE (CursX):

The solid trace cursor position is normally controlled by the right and left cursor (arrow) keys, and the alternate (dashed) cursor is controlled by ALT-right and ALT-left cursor keys. This situation is reversed when CursX (Cursor eXchange) is active. You may want to set this so that the most-used cursor for a particular series of measurements will not need the extra ALT key. Note that this function may be toggled by either the C-key, as shown in the key option area, or by the grey minus-key, which is more convenient for quick one-hand operation if you are using the number pad for cursor control.

The trace cursor "feel" may be controlled via options in the Keyboard Control menu (CTRL-K).

KEYBOARD CONTROL UTILITY:

XKBD.EXE is a small utility program that allows direct setting of the AT keyboard controller auto-repeat parameters, which in Daqarta are set via Hardware Delay and Rate.

You invoke it from the command line or from a batch file with two parameters, as in:

    XKBD 0,31

The first parameter controls the initial delay before the auto-repeat function begins:

 0 = 250 msec       2 = 750 msec
 1 = 500 msec       3 = 1000 msec

The second parameter controls the repeat rate (chars/sec):

 0 = 2.0      8 = 4.0     16 = 8.0      24 = 16.0
 1 = 2.1      9 = 4.3     17 = 8.6      25 = 17.1
 2 = 2.3     10 = 4.6     18 = 9.2      26 = 18.5
 3 = 2.5     11 = 5.0     19 = 10.0     27 = 20.0
 4 = 2.7     12 = 5.5     20 = 10.9     28 = 21.8
 5 = 3.0     13 = 6.0     21 = 12.0     29 = 24.0
 6 = 3.3     14 = 6.7     22 = 13.3     30 = 26.7
 7 = 3.7     15 = 7.5     23 = 15.0     31 = 30.0

If you are using DOS 5 or later, you can do this with the MODE CON command instead, although operation is slightly different. Unlike some similar utilities, XKBD is NOT memory-resident.

Regardless of whether you use XKBD or MODE CON, you will only be able to control AT-type keyboards (84 keys or more). These utilities program the controller chip that is inside the keyboard itself, not in the system unit. Older PC/XT-type 83-key keyboards do not have a programmable controller chip, so even though you may use one of these with an AT system unit, there is nothing that can be changed. Conversely, many keyboards have a switch that allows AT or XT operation, but even if you use one of these with an XT, the XT lacks the ability to generate the signals needed to set the controller chip.

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