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Forum Index : Microcontroller and PC projects : MM Basic - INKEY$
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BobD Guru  Joined: 07/12/2011 Location: AustraliaPosts: 935 |
When I build a menu I like to use a single keystroke entry without the need for a <CR>. In my thinking it leads to a clean UI. So I have been using INKEY$ as the means of getting the keystrokes. While doing that I ran across some difficulties. The following code does not work. All I get is the loop exits but I get null values presented. ? " Tell me what to do"
do loop until inkey$ <> "" k=val(inkey$) on k gosub dummy, dummy, dummy, dummy, dummy, dummy, dummy, dummy, dummy After some experimentation I have this code which works. ? " Tell me what to do > ";
Do k$=Inkey$ Loop Until k$ <> "" k=Val(k$) On k GoSub dummy, dummy, dummy, dummy, dummy, dummy, dummy, dummy, dummy Ignore the "gosub dummy". I build my front end first and then as I finish the work modules I then include access to them, in this case via the "on k gosub". Until it is all finished I have a subroutine named Dummy: which does nothing but return. My conclusion is that INKEY$ only has a valid value until the first access after it is set and if you want to continue use of that value then it has to be saved as in "k=val(inkey$)". Is this correct? Are there any other variables that may work similar? MM.I2C may be another one but I haven't tried it. |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2914 |
Hi Bob, I think your synapses is correct. You are basically doing TWO Inkey$ tests the first one exits your loop and the second one returns a NULL so doesnt work. It is standard practise to assign a variable to the Inkey$ read and then test it as you have done in your second example. Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
Inkey$ is a Pseudo-variable. It obtains the current keypress value each time it is used. Therefore as BIGMIK stated you need to assign the value to a variable to allow you to use it in the manner you wish. VK4MU MicroController Units |
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