How to read analog signals?

[Bruce]

Here's an example of reading an analog voltage with a 12F683. I'll let you figure out the LED part...;}

@ __CONFIG _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_OFF & _CP_OFF

    DEFINE OSC 8            ' Internal 8MHz 
    DEFINE DEBUG_REG GPIO   ' Define DEBUG port
    DEFINE DEBUG_BIT 1      ' Set GPIO.1 as DEBUG serial output pin
    DEFINE DEBUG_BAUD 9600  ' DEBUG baud rate = 9600 bps
    DEFINE DEBUG_MODE 1     ' 1 = inverted, 0 = true
    
    DEFINE  ADC_BITS 10     ' 10-bit resolution
    DEFINE  ADC_CLOCK 5     ' Set clock source to Frc/16
    DEFINE  ADC_SAMPLEUS 50 ' Sample time in uS before A/D conversion is started
    Quanta  CON 1251        ' For 10-bit A/D +Vref = 5V : 5V/1023*256=1.251=Quanta

' PIN# NAME     USE & CONNECTION
'  1   Vdd      +5VDC power supply
'  2   GPIO.5   N/C (N/C = NO CONNECTION)
'  3   GPIO.4   N/C
'  4   GPIO.3   N/C
'  5   GPIO.2   N/C
'  6   GPIO.1   Serial output pin to PC serial port RX pin
'  7   GPIO.0   A/D input pin
'  8   Vss      Power supply ground (also connect to DB-9 pin #5)
'-------------------------------------------------------------------------

    CMCON0 = 7          ' Disable comparator
    ANSEL = %00000001   ' Set GPIO.0 to A/D
    ADCON0.7 = 1        ' Right justify for 10-bit
    TRISIO = %00000001  ' GP.1 = serial out, GPIO.0 = A/D in, rest outputs
    OSCCON = %01110000  ' Internal 8MHz osc
    ADval  VAR WORD	' A/D conversion result

MAIN:
    ADCIN 0, ADval      ' Read A/D
    ADval = ADval */ Quanta
    DEBUG DEC ADval DIG 3,".",DEC3 ADval,"~"
    PAUSE 200
    GOTO MAIN

    END

[thm ov3rkill]

Hey bruce thanks a lot Bielive it or not i learned a lot form that small little part I as wondering if You can read the analog and pulse low on the same pin?

[thm ov3rkill]

I did a little bit more research on this But its pretty hard what i wanted to do is read a analog voltage off a circiut board andif that reading is true I want it to pulse low through the same pin reading the voltage will this be possible?


edit: bruce can you help me explain what ever line means it will give me a betetr understanding of how to see if i can use the if then statment to flash the led

[Archangel]

I did a little bit more research on this But its pretty hard what i wanted to do is read a analog voltage off a circiut board andif that reading is true I want it to pulse low through the same pin reading the voltage will this be possible?


edit: bruce can you help me explain what ever line means it will give me a betetr understanding of how to see if i can use the if then statment to flash the led

Here is the hangup in your question:In English, True / False statements are digital statements, so when you say, "and if that reading is true ". . . we are not sure what you want "true" to represent. Please explain further . . . Does " true" represent a specific voltage, or just any voltage? Are you trying to test for a specific voltage? Bruce gave you the code above to receive the value of the voltage, so what do you want to do with that information?

[thm ov3rkill]

well joe thanks for replying what I want to do is... I want to be able to test a analog voltage peroid. And if that analog volatge is in fat true then I want it to pulse low out of the same pin testing that voltage.

edit i dont want to see how much the voltage is i want to see when it read analog

[LinkMTech]

edit i dont want to see how much the voltage is i want to see when it read analog

I'm taking a stab at this. I believe when you say "true" you are wanting to say "through", meaning "complete" or "done", is this correct?
And if that is the case, then it can be done but your circuit will have to be made to monitor your analog signal and have an LED at the same pin.
It would be simpler to use one pin for the analog signal input then turn ON an LED on another pin (setup as an output) when the A/D is completed or "through".

[Archangel]

I want to be able to test a analog voltage peroid.

Ok you want to test an analog voltage, what are you testing for? Do you mean any value greater than zero ?

And if that analog volatge is in fat true then I want it to pulse low out of the same pin testing that voltage.

edit i dont want to see how much the voltage is i want to see when it read analog

So if I understand correctly . . .

 
If voltage is > 0 then
PortA.0 = 0 'set port latch to low status before enabling tris
TRISA.0 = 0 ' Turn input into output enabling port to pull low.
else
TrisA.0 = 1 ' Keep port in high impedance input status
endif

Where PortA.0 in this example is your analog input / output port

[thm ov3rkill]

Hey joe Well this is the thing I want to setup a little project . You may remmeber me from the xbox 360 thread. But i didint get a chance on that. So i wanted to seeif i can acually get to read the trigger press and pulse out.


Also I wanted this to be done on a pic 12f683

Well The reason i want it on the same pin because I dont think i can kill 2 birds with one stone meaning as There is only on spot to read and fire of the controller which is called the wiper. I have seen this done before. So lets say i pull the trigger the pic reads the analog then it pulses low.