get a sensor digital input to work on a pickit 2 16f690 lpc

[Jasonstew]

First is it possible to run a low voltage digital sensor switch to work on this board and how?

[Archangel]

Hi Jasonstew,
Please give a bit more detail, I am pretty sure the answer is yes. What voltage and type of sensor do you want? Digital or analog ?

[Jasonstew]

As i said it will be a digital sensor and i believe the voltage is 5 volts, the same as the pickit 2

[Heckler]

Why would you think or wonder that it would not work?

Have you tried it?? If so what problems did you encounter?

As Archangel indicated you need to provide enough detail to back up your question.

[Jasonstew]

I was just wondering how to use digital sensors on PIC's

[Heckler]

Can you give a specific part number of the sensor?
or some example code that you have tried?

I(we) are quite willing to helpl but need enough detail so that the question can be addressed.

As you probably know, there are litterally hundreds of digital and analog sensors.
Are you trying to sense light, temperature, sound, mass, movement?

Here is an article showing how to interface with one or many "Dallas Semiconductor 1-wire Temperature sensors (DS18B20)"

http://www.picbasic.co.uk/forum/content.php?r=374-How-to-read-a-one-wire-DS18B20-temperature-sensor-or-nine-of-them

[Archangel]

Well JasonStew,
Digital is simple, if you have the 5 v it is a one and if not it is a zero, so set one of the ports to input, just for hoots I will say PortB.7 like so TRISB = %10000000 and now portb.7 is an input. Now really simple Psuedocode If Portb.7 = 1 then portb.6 = 1 and viola if portb.7 is switched on then it switches the output on portb.6 to on status. You see I set the other 3 usable ports on PortB as outputs in the tris statement. I think it causes less confusion if you get in the habit of using all 8 bits in your port and register declarations even when the port has "unimplemented" bits like the 4 lower bits(ports) in portb of the 16f690. When you setup the ports and tris registers, it seems counter intuitive but set the port register first then set up the tris register. That way any outputs are set to the desired state before they become outputs (THANKS BRUCE ).

[Jasonstew]

Thank you I was successful with that now how would i do it with an analog sensor with similar voltages

[Jasonstew]

Also with the digital sensor program, the light turns on when the state changes, but won't shut off unless i push the button on the lpc. Why? Thanks again. This is the code:


'-------------------------------< Blinky LED >------------------------------------
'
' File name : BlinkyLed.bas
' Version : 1.0
' Company : Mister E
' Programmer : Steve Monfette
' Date : June 22, 2011
' Device : PIC16F690
'
'---------------------------------------------------------------------------------

'---------------------------< Project description >-------------------------------
'
' Beginner code example to blink a Led on PORTc.0 using:
' 1) PBPDEMO version
' 2) MicroCode Studio
' 3) PICKIT 2 Programmer
'
'---------------------------------------------------------------------------------

'----------------------------< Hardware listing >---------------------------------
'
' - Microchip Low Pin Count Demo Board
' - PIC16F690 installed
' - *** All jumper have to be installed ***
' - Target board will be powered by the PICKIT 2
'
'---------------------------------------------------------------------------------

'
' Pic Configuration
' =================
' All PIC configuration fuses (Configuration bits) are listed in the
' C:\PBPDEMO\p16f690.inc file. Also see datasheet section 14.1
'

' _INTRC_OSC_NOCLKOUT: Using Internal Oscillator
' _WDT_ON: Enable Watch Dog Timer
' _MCLRE_ON: Enable MCLR
' _CP_OFF: Disable Code Protection
' _CPD_OFF: Disable Data Code Protection
' _FCMEN_OFF: Disable Fail Safe Clock Monitor
' _IESO_OFF: Disable Internal/External switchover
' _BOR_ON: Enable Brown out detect
' _PWRTE_ON: Enable Power up Timer
'
OSCCON = %01110000 ' datasheet section 3
' -x-------- n/a
' --111----- IRCF<2:0> Internal Oscillator Frequency Select Bits (8MHz)
' -----xxxx- Read Only
'
DEFINE OSC 8 ' tells PBP we use a 8 MHZ clock

'
' Hardware assignment
' ===================
' Here we assign Aliases to PORT pin
' this makes the code easier to read
' I'll use the Aliases name as written on the schematic
'
' LEDs
' ----
DS1 VAR PORTC.0
DS2 VAR PORTC.1
DS3 VAR PORTC.2
DS8 VAR PORTC.7


'
' Hardware configuration
' ======================
'
' I/Os (Datasheet section 4.0 & above)
' ------------------------------------
TRISA = 0 ' All PORTA I/O set as Output (When capable of)
TRISB = 0 ' All PORTB I/O set as Output
TRISC = 0 ' All PORTC I/O set as Output
'
' ADCs (datasheet section 9)
' --------------------------
ANSEL = %00000000 ' Set all pins digital

ANSELH = %00000000
WPUA = %00000011 ' Enable pullups for buttons
WPUB = %00000000

'
' Comparator (datasheet section 8)
' --------------------------------
' At Power On, the comparator are already disabled
' but let's play safe.
'

CM1CON0 = 0 ' Disable comparator 1
CM2CON0 = 0 ' Disable comparator 2

'
' Software/Hardware initialisation
' ================================
PORTA = 0 ' clear PORTA output pins (0v)
PORTB = 0 ' clear PORTB output pins (0v)
PORTC = 0 ' clear PORTC output pins (0v)

WHILE !OSCCON.2 : Wend ' Wait untill the internal OSC get stable

i Var Byte
'------------------------------< Main program >-----------------------------------
'
START:
iF (PORTC.7= 1) THEN
PORTC.0 = 1
ELSEIF (PORTC.7 != 1) THEN
PORTC.0= 0
ENDIF
PAUSE 1000
PORTC.0=0

GOTO Start





'

[Heckler]

Hey Jason... Looks like you are making progress. At least you are getting LED's to blink, instead of fighting with compilers.;)

I have not tried your example program above, but you might try reversing the order of your "IF" statements.

your code:

START:
iF (PORTC.7= 1) THEN
PORTC.0 = 1
ELSEIF (PORTC.7 != 1) THEN
PORTC.0= 0
ENDIF
PAUSE 1000
PORTC.0=0

GOTO Start




With the IF statements reversed:

START:
IF PORTC.7 = 0 THEN
PORTC.0= 0

ELSEIF PORTC.7= 1 THEN
PORTC.0 = 1

ENDIF
PAUSE 1000
PORTC.0=0

GOTO Start



How about this...


Start:
PortC.0=PortC.7
Pause 1000
goto Start


If you are useing the LPC demo board the push button is tied to MCLR which is resetting your PIC each time you push it, thus causing the LED to go off because you set portC =0 in your program.

In order to do something similar with an analog sensor you would configure the pin as an analog input instead of digital... I will try and dig up a simple analog example and post it.

One good tool that I find helpful would be to search on 16F690 and just look at various examples and try to see what others have done. Also look through various code examples in the "WIKI" section at the top of the forum. You might also look over on the MELabs web site, where they have several code examples for various PIC functions.

PS. instead of using the Quote function to display code in your posts... Move over to the next icon "#" which is used to post code examples.

[Archangel]

OK Jasonstew,
Here is a code that makes "cylon" eye pattern, and speed will be controled by the rheostat on your board.


@MyConfig = _INTRC_OSC_NOCLKOUT & _WDT_OFF & _PWRTE_ON
@MyConfig = MyConfig & _MCLRE_OFF & _BOR_OFF
@ __config MyConfig

DEFINE OSC 4
DEFINE ADC_BITS 8
DEFINE ADC_CLOCK 1
DEFINE ADC_SAMPLEUS 50
PortA = 1
PortB = 0
PortC = 0
TRISA = 1
TRISB =%01010000
TRISC = %00000000
i var word 'locks up @ 255 with byte
ANSEL = 1
ANSELH = 0
CM1CON0 = 0
CM2CON0 = 0
Backlight Var word


main:


ADCIN 0,BACKLIGHT

for i = 1 to 255
portC = i
i=i << 1 - 1
pause backlight
next i
for i = 255 to 1 step -1
i=i >> 1 + 1
portc = i
pause 25
next i

goto main
end

Do not make too much over the variable names, I recycled some code in this.

[mister_e]

Also with the digital sensor program, the light turns on when the state changes, but won't shut off unless i push the button on the lpc. Why? Thanks again. This is the code:
In your code, your TRISC line is not right, you must set some inputs there.... as it is right now, there's only OUTPUT. Change it to


'
' 76543210
TRISC = %10000000
' -1-------- PORTB.7 = INPUT
' --0000000- PORTB<6:0> = OUTPUT
And then your main loop may looks like...


Start:
IF PORTC.7 = 1 THEN
PORTC.0 = 1
ELSE
PORTC.0 = 0
ENDIF
PAUSE 1000
GOTO Start
OR.. WAY easier


Start:
PORTC.0 = PORTC.7
PAUSE 1000
GOTO Start

In your code, you enable the Pull up on PORTA, there's no internal pull-up available for PORTC, so I hope you have one ;)

[Jasonstew]

mi pickit2 constantly gets busy after around 15 seconds and i am forced to recompile why?

[ScaleRobotics]

That's because of your code in line 11.

Just kidding, how could we possibly know what the problem might be from what you wrote? So now I am going to sound like a teacher and ask for at least a sentence for each of these topics. (Nah, a teacher would have asked for a paragraph on each)

1. Gets busy? Busy doing what?

2. 15 seconds after what?

2. Recompile, what is forcing you to do this, and why?

3. What are you doing to get here?

4. Any errors?

5. Any code?

[mister_e]

6. Are you using the PICKIT 2 Standalone application, or the command line? If so, make sure you don't run 2 instances (or more) of the application.

7. What if you change TRISA to...


TRISA = 255

[Jasonstew]

The problem was solved whjen i changed the code to portc.0 = portc.7. Thanks.