Wait for 1 of 3 inputs to go high

[smeagol]

Hi all,

I'm sure it's due to old age but I'm having serious brian fade.

I have 3 inputs and want the program to wait until one of them goes high.

[color=Black]WaitForButton:[/color]
[color=Blue]do
loop while [/color][color=Purple]Buttonset [/color][color=DarkCyan]<> [/color][color=Navy]1 [/color][color=DarkCyan]or [/color][color=Purple]buttonup [/color][color=DarkCyan]<> [/color][color=Navy]1 [/color][color=DarkCyan]or [/color][color=Purple]buttondown [/color][color=DarkCyan]<> [/color][color=Navy]1[/color]

I would expect this code to sit in the do loop until one input goes high as it is ORing the inputs.

What it actually does is wait for all inputs to go high at the same time.

Where am I going wrong?

Cheers

 

[hippy]

I think you have a logical condition error ...

do
loop while Buttonset <> 1 or buttonup <> 1 or buttondown <> 1

Is the same as ...

do
loop while Buttonset = 0 or buttonup = 0 or buttondown = 0

Which will loop while any of the buttons is low, will only continue when all buttons are high.

You probably want one of the following ...

loop until Buttonset = 1 or buttonup = 1 or buttondown = 1

or

loop while Buttonset = 0 and buttonup = 0 and buttondown = 0

 

[smeagol]

Cheers Hippy

I think you have a logical condition error ...

loop until Buttonset = 1 or buttonup = 1 or buttondown = 1

That one does exactly what I want

I'll never be be able to pretend to be a Vulcan, I'm obviously not logical enough

 

[MikeM100]

I know this has been sorted but how about a cheapo 'Micky Mouse Logic (M2L) gate

 

[tmfkam]

That's my kind of logic...

 

[westaust55]

I know this has been sorted but how about a cheapo 'Micky Mouse Logic (M2L) gate

Yes great, simple and cheap.

However, if the OP wanted to later be able to determine the cause of the change then it would still be necessary to bring each signal directly into the PICAXE on separate pins.

Depending upon the complexity of the OPs project code, using SETINT is another possibility which can monitor for any one (or more) of the three signals going high.

 

[Circuit]

If you can wire the three buttons onto one port then the easiest solution is to monitor for ANY changes in the port.
e.g.
On an 18M2, this would work for eight buttons;

    [color=Blue]let [/color][color=Purple]dirsB[/color][color=DarkCyan]=[/color][color=Navy]%00000000 [/color][color=Green]; this sets portB pins as inputs.
'Then set the state of this port into a variable;
    [/color][color=Blue]let [/color][color=Purple]b1[/color][color=DarkCyan]=[/color][color=Purple]PinsB[/color]
[color=Green]'Record this state in another variable:
    [/color][color=Blue]let [/color][color=Purple]b0[/color][color=DarkCyan]=[/color][color=Purple]b1[/color]
[color=Green]'Then test b0 for any change in a loop
    [/color][color=Blue]do
        let [/color][color=Purple]b1[/color][color=DarkCyan]=[/color][color=Purple]PinsB
        [/color][color=Blue]if [/color][color=Purple]b0[/color][color=DarkCyan]<>[/color][color=Purple]b1 [/color][color=Blue]then exit
    loop[/color]

Upon exiting the loop you can isolate which switch has changed.

 

[westaust55]

Another options where the signals are from three pushbuttons is to use a single ADC (Analog) input with differing values of resistor associated with each switch and a pull down resistor.
Then a low value (from pull down) when no button is pressed and differing higher voltages towards Vcc when a switch is pressed. The value received from the ADC can be used to identify which switch(es) are pressed.