Dial switch diemna... need more ANalog ports

[lerameur]

hello,

I I am using the pic16f88 and I do not wish to change chip, but my dilemna is that I need more analog port. I want to add a selection button, where if you set the dial button on 1 it will put AN1 high, if dial button is set on 2 then AN2 will be high etc...
I need 7 selection (so seven input pin) but I am only left with 3 ports to use.
Is there anything like a analog to digital switch? or an alternative to either the switch or anything else that will give the same result?

thanks
K

[mackrackit]

Maybe use the POT or RCTIME command.

[lerameur]

yes I need a pot switch, But I never seen one that has grooves in them so it do not change position by its own .. does that exist??

K

[Ioannis]

They do exist and I think is called detent.

Look in ALPS.

Ioannis

[LinkMTech]

You can configure your own "switching" pot with a 7 position switch and resistors then use only 1 A/D port.

The values selected were not calculated for anything special just picked something that would probably give a decent spread for a 10bit A/D setting. Then using the SELECT CASE, set the values to the level "between" each setting.
Suppose position 1 value is 170 and position 2 is 327 then make your 1st CASE setting to 248, middle of the two values, and continue from there for the whole range.

Sample code:

check_switch:     
    ADCIN #, adval    
    SELECT CASE adval
        CASE IS < xxx: do this or that   ' Lowest value
        ......
        CASE IS < xxx: do this or that   ' Highest value   
    END SELECT    
RETURN

I just made this a couple of months ago and works as needed!

[lerameur]

thats agood idea, I used a similar switch arrangment but I will drop my if then statement and use Select case, I dod not know it was in picbasic, I used it in C++ a long time ago.
thanks

L