Stable ADC readings

[mister_e]

Simple, there's no voltage in there as it is right now. You'll need to modify the circuit to add some voltage there. The pull-up thing should work.

Do yourself a big favor, output the value of the ADC reading to a LCD or to your computer, push on a single button, note the value and modify the IF-THEN value in the code.

What are your pull-up value?

[Ioannis]

On F877 or F877A there are NO pull-ups on port A. Only on Port B.

Ioannis

[mister_e]

Check this thread, seems you want to do something really alike
http://www.picbasic.co.uk/forum/showthread.php?t=15229&

[mazoul72]

10k for pull up external.
i have only two wires to tie at right and two wires to tie ar left of steering wheel.
So 12 buttons in fact .
If i tie like the thread you provided , so many wires and this is the first part of entire PIC system .
i am not sure there are enough wires after this.
I have 25 inputs/outpouts tie to PIC .(without components reserved operation )
Perhaps the eight outpouts/input reserved to LCD (for test before FIS tachometer connected) .

[mister_e]

The link I provided was about the OUTPUT not the input. It show how to connect your resistor and how to code it.

your whole system to the car should be more than 6 wire... but 3 of them should already be GND or +5v/+12V.

Plug the steering wires, push on each button, for each button you have a diffferent ADC reading.

OR use a multimeter and measure the resistor value when you push on a single button.... also when you don't push on any button. From there we can also work out a solution.

Also, we still have NO information about your radio, no brand, no model no nothing. At least do you know the resistor value needed for each function?

[mazoul72]

Yes i tried last month , i have the value.
I have already put schematic.
my radio is pioneer 6900IP , only a jack remote input.

My intension is to keep the wires buttons .
With more wires , i have to change all connections.

[mister_e]

I know the input... how about the output?

BTW, as per the service manual, this radio seems to use a stereo Jack... maybe you need a resistor on the tip, another on the ring? Whatever, the method on the previous link will work for the OUTPUT section.

[mazoul72]

I try assembler but i have some errors

[mister_e]

Assembler, C, Fortran or Pascal will not solve the problem here. The problem is not the ADC reading, it is what you do with.

[mazoul72]

the soft ? picbasic pro ?????
i have the same error with mplab
thanks to be explicit .
it is an example from a guy - it works for him !
it is not easy to spend all days to arrive ( only ADC) to nothing !

Herve

[mister_e]

Hervé, je veux bien t'aider du mieux que je peut, mais tu va devoir faire une partie des devoirs de ton coté.

Ok, let's observe the schematic you posted


OK, please answer the following question:

Q1: The Resistor attached to the button are built-in the remote/Steering and you can't modify anything in right?

A1:_______________________________________

Q2: You have a 10K pull-up On RA0, and another on RA1... true?

A2:________________________________________

Q3: If so, assuming you don't push on any button, Between GND and RA0 AND between GND and RA1 with your multimeter you should read something like 1.4Volt RIGHT?

A3:________________________________________

From there, we need to etablish at least 4 conditions
1) ADC reading when no push button are pressed
2) ADC Reading when you push on Button 1 alone
3) ADC Reading when you push on Button 2 alone
4) ADC Reading when you push on Button 3 alone

We can use maths to do so OR output each ADC reading to a LCD OR send the data do your PC via serial communication OR store them in the PIC EEPROM. Choice is yours. Let's see if the maths could work here.

Without any push button pressed, I said around 1.4. Using the voltage divider theory
(3902/(3902+10000))*5 = 1.403

so the ADC should return something like
(1.4/5)*1023 = 287

Do the same with the other resistor value and you should be able to evaluate
1) when no push button are pressed
V = 1.4
ADC Reading = 287

2) When you push on Button 1 alone
V = 0.37
ADC Reading = 76

3) When you push on Button 2 alone
V = 0.58
ADC Reading = 119

4) When you push on Button 3 alone
V = 0.82
ADC Reading = 168

Now, try this.

'
'       Hardware setup
'       ==============
        '
        '       I/O
        '       ---
        TRISA = %00000011       ' RA0 et RA1 en entrée
        TRISB = 255             ' Disconnect all resistor from the circuit
        PORTB = 0               '
        '
        '       ADC
        '       ---
        DEFINE ADC_BITS 10      ' Set number of bits in result
        DEFINE ADC_CLOCK 3      ' Set clock source (rc = 3)
        DEFINE ADC_SAMPLEUS 50  ' Set sampling time in 
        ADCON1 = %10000010      ' RA0 à RA3
                                    
'
'       Software Variable
'       =================
        ADRes       VAR WORD    ' ADC Reading
        BTN         var byte    ' Data to be sent to PORTB
        i           VAR BYTE    '
        ADCChannel  VAR BIT     '
        ADCButton   VAR BYTE [3]'
'
'       Software constant
'       =================
        ADCSafety   CON 10              ' min/max range for ADC Reading
                                        '
        ADCNone     CON 287 - ADCSafety ' 
        ADCButton[0]  = 76              ' button 1 or 4 
        ADCButton[1]  = 119             ' button 2 or 5 
        ADCButton[2]  = 168             ' button 3 or 6 
                      
Start:  
        TRISB = 255                     ' Disconnect all resistor from the circuit  
        ADCIN ADCChannel,ADRes          ' Read ADC
                                        '
        if (ADRes < ADCNone) Then       ' Any button down?!?
                                        ' - Yes!
                FOR i = 2 TO 0 STEP -1  '   Loop through all 3 calculated posibilities
                                        '   Test against calculated ADCresult
                                        '   and allow a range of +/- ADCSafety
                        IF (ADRes > (ADCButton[i]-ADCSafety)) AND  (ADRes < (ADCButton[i]+ADCSafety)) THEN
                                        '   Valid ADC result, clear the coresponding I/O
                                TRISB = ((DCD i) << (ADCChannel*3)) ^255
                                PAUSE 200
                                i=0     '   and getOut of here
                                ENDIF   '
                                        '
                        NEXT            '
                                        '
                else                    ' - NO!
                                        '   Switch to the other ADC channel
                ADCChannel = ADCChannel ^ 1 
                ENDIF
        GOTO Start                      '

Button 1, enable PORTB.0, Button 2 PORTB.1 etc etc.

For testing purpose use LEDs to VDD. It works here.

[Ioannis]

I Bet there are no pull ups on port A inputs.

Ioannis

[ivanrosales]

mazoul72, I'm really new to picbasic, but I note in your schematic that you don't have pull-up resistor, so please try something like this:


Also, try to code something like the below example, if you rotate the bits of your ADC reading, you can leave only the 2 most significating bits, this way, you can know the exact button pressed (of course you must calculate correctly the resistors values):

DEFINE ADC_BITS 8
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50

ADVal var byte
Switch var byte

Principal:
adcin 3,adval
switch = (adval >> 6) 'Shift for 2 MSB for values 0 to 3 representing each button

SELECT CASE switch
CASE 0
'Put your code here
gpio=0
CASE 1
'Put your code here
high gpio.0
CASE 2
'Put your code here
high gpio.1
CASE 3
'Put your code here
high gpio.2
END SELECT

goto principal
end

[mister_e]

Post #44

10k for pull up external.

I guess it's an omission on it's schematic. At least I hope

[ivanrosales]

That's right Master mister_e, he mention the 10k pull-up before, but I want to be sure he is assembling his circuit properly (just to have peace of mind)

By the way Master, I'm new to this forum as well to picbasic and since I first read your posts you became my "Personal Jesus"
Regards!

[mister_e]

Don't do that, Depeche Mode have some Copyright on that quote

Welcome aboard!

[mazoul72]

Hello,
First many thanks to your answers .

OK, please answer the following question:

Q1: The Resistor attached to the button are built-in the remote/Steering and you can't modify anything in right?

A1:_Yes , it is too little inside because it is cms components .

Q2: You have a 10K pull-up On RA0, and another on RA1... true?

A2: Yes , it is an omission but it is 10Komhs for test ( 3.96 Volts with no action)

Q3: If so, assuming you don't push on any button, Between GND and RA0 AND between GND and RA1 with your multimeter you should read something like 1.4Volt RIGHT?

A3: No , i read 3.96 Volts on 10K resistors and RA0,RA1.

So , (3902/(3902+10000))*5 = 1.403 .
i will verify if there is another resistors but i see 3902 ohms (i am sure) , perhaps an error . I will tell you about.

I don't understand : TRISB = ((DCD i) << (ADCChannel*3)) ^255



Best regards
Hervé

[mazoul72]

i don't know why 3.96 V and not 1.4 V ....

[mister_e]

3902 is actually 39K, so the other resistor are also bad... ok then. So be it.

modify what's in red

'
'       Software Variable
'       =================
        ADRes       VAR WORD    ' ADC Reading
        BTN         var byte    ' Data to be sent to PORTB
        i           VAR BYTE    '
        ADCChannel  VAR BIT     '
        ADCButton   VAR WORD [3]'
'
'       Software constant
'       =================
        ADCSafety   CON 10              ' min/max range for ADC Reading
                                        '
        ADCNone     CON 814 - ADCSafety ' 
        ADCButton[0]  = 90              ' button 1 or 4 
        ADCButton[1]  = 164             ' button 2 or 5 
        ADCButton[2]  = 270             ' button 3 or 6

should work

This is Why I asked to measure with your ohmmeter a couple of post back... and nope I'm not going to decipher a PCB

You have everything on hand....

[mister_e]

I don't understand : TRISB = ((DCD i) << (ADCChannel*3)) ^255

Check your manual about DCD, logical and bitwise operators. It's all there

Anyone wants to explain it?

Yes I've put some black magic in

[mazoul72]

Hello Steve ,

i have some erratic values on BTN result ( BTN = TRISB ) under pic smulator ide 6.91 .
like 1 . 2 . 4 .255 and cycle infinite .

But i will try this evening on led test or resistors.

I note in 16f877x datasheet that with "1" TRISB , we have High Impedance so we can choose whose resistor to be put off .
But with other state bit of TRISB , i don't understand how tie to common +5V of car radio (TIP) to the RB0,RB1,RBx..... ???
We have agree that it is a result of a resistor between common ground (sleeve) and +5V (tip) on jack "grip" .

Hervé.

[mister_e]

Never trust a sim... as simple as that. They're on the market for laziness and to make good money out of it. Good enough to replace any xBox, Nintendo... or some porn.

You tie the resistor like the guy in that previous thread. One side on the PIC the other side are tied together and sent to the Radio.

[mazoul72]

Hi Steeve,

i test intensity value with some résistors tie together to one led.

But with your program , trisb stay at 255 , i put some select case for test but no trisbx.0 work (255 always)
I will try to my test platine .
I understand your "voodoo formule" , it is for have only one button put on , no action with 2,3 .. together .

Regards.
Hervé

[mazoul72]

i repeat my question :
how tie the resistors on the side of PIC together to have a resultant resistor in parallele ?
i agree that the other side is tie together to the radio , but on the ground ,yes
but the +5V for PIC RBx ?

Regards.

Hervé

[mazoul72]

in fact , the simulator isn't reactif with adc , i must go slowly with an0/an1 choice .
But step by step around button(i) , it works.

I must add six other buttons in programm and .

[mazoul72]

Can i use btn as word variable for a select case like 1110111111111111 ?
(with your formule dcd(i).... )
i can't for the moment ...
i use adcchannel 0 to 3 .

Regards.
Hervé

[mister_e]

pbp 3 manual section 2.12

[mazoul72]

Hello,

it works all !
great and many thanks.

I made another "formule" in addition to yours (to work with 12 buttons and 4 channels__3 buttons on a wire)
It is perhaps not proper .
I add to this : PIC Simulator IDE 6.91 works great , all test with it and great.


. btn = ((DCD i) << (ADCChannel*3))^255
. if ADcchannel = 3 and btn = %11111111 then btn = (btn - (3*adcchannel)) << i
. gosub choose
..
..
ADCChannel = ADCChannel + 1 'Switch to the other ADC channel
if ADCchannel = 4 then adcchannel = 0
..
..
choose:
select case btn
' first bloc of 6 buttons
case %11111011 ' AN0-270 --- 47k and 5k = 4.6k
TRISB.0 = 0 ' 5k and 5k = 2.5k
TRISB.1 = 0
case %11111101 ' AN0-164 --- 47k and 10k = 8.2k
TRISB.1 = 0 ' 5k and 5k = 2.5k
TRISB.2 = 0 ' 47k and 47k = 22k
case %11111110 ' AN0-90 --- 47k and 22k = 15k
........


Regards
Hervé

[mazoul72]

i am so disapointed because it doesn't work on test real card and works on simu.
strange...
i have microcode studio with 15 days trial .(compiler 3.0.0.1)

TRISA = %00001111 ' RA0 et RA1 en entrée

TRISB = 255 ' Disconnect all resistor from the circuit (Haute impédance)

PORTB = 0 '

'

' ADC

' ---

DEFINE ADC_BITS 10 ' Set number of bits in result

DEFINE ADC_CLOCK 3 ' Set clock source (rc = 3)

DEFINE ADC_SAMPLEUS 50 ' Set sampling time in

ADCON1 = %10000010 ' RA0 à RA3 and RIGHT JUSTIFIED



'

' Software Variable

' =================

ADCRes VAR WORD ' ADC Reading

btn var byte ' Data to be scan

i VAR BYTE '

j var bit

ADCChannel VAR byte '

ADCButton VAR word [3]'

'

' Software constant

' =================

j = 0

ADCSafety CON 10 ' min/max range for ADC Reading

'

ADCNone CON 814 - ADCSafety '

ADCButton[0] = 90 ' button 1,7 or 4,10

ADCButton[1] = 164 ' button 2,8 or 5,11

ADCButton[2] = 270 ' button 3,9 or 6,12



Start:

TRISB = 255

ADCIN ADCChannel,ADCRes ' Read ADC

'

if (ADCRes < ADCNone) Then ' Any button down?!?

' - Yes!

FOR i = 2 TO 0 STEP -1 ' Loop through all 3 calculated posibilities

' Test against calculated ADCresult

' and allow a range of +/- ADCSafety

IF (ADCRes > (ADCButton[i]-ADCSafety)) AND (ADCRes < (ADCButton[i]+ADCSafety)) THEN

' Valid ADC result, clear the coresponding I/O

btn = ((DCD i) << (ADCChannel*3)) ^255

if (ADcchannel = 3 and btn = 255) then btn = ((btn - (3*adcchannel)) << i)

gosub choix

pause 200

i=0 ' and getOut of here

ENDIF '

NEXT '

else ' - NO!

ADCChannel = ADCChannel + 1 'Switch to the other ADC channel

if ADCchannel = 4 then adcchannel = 0

ENDIF

GOTO Start

choix:

select case btn

' premier bloc de 6 boutons
case %11111011 ' AN0-270 --- 47k and 5k = 4.6k

TRISB.0 = 0 ' 5k and 5k = 2.5k

TRISB.1 = 0

case %11111101 ' AN0-164 --- 47k and 10k = 8.2k

TRISB.1 = 0 ' 5k and 5k = 2.5k

TRISB.2 = 0 ' 47k and 47k = 22k

case %11111110 ' AN0-90 --- 47k and 22k = 15k

TRISB.2 = 0

TRISB.3 = 0 ' 10k and 10k = 5k

case %11011111 ' AN1-270 --- 47k and 2.2k = 2.1k

TRISB.3 = 0 ' 47k and 15k = 11.3k

case %11101111 ' AN1-164 --- 100k and 22k = 18k

TRISB.4 = 0 '

TRISB.0 = 0 '

case %11110111 ' AN1-90

TRISB.5 = 0

TRISB.1 = 0

TRISB.3 = 0

' deuxième bloc de boutons

case %11111111 ' AN2-270 --- 47k and 5k = 4.6k

TRISB.7 = 0 ' 5k and 5k = 2.5k

TRISB.6 = 0

case %01111111 ' AN2-164 --- 47k and 10k = 8.2k

TRISB.5 = 0 ' 5k and 5k = 2.5k

TRISB.4 = 0 ' 47k and 47k = 22k

case %10111111 ' AN2-90 --- 47k and 22k = 15k

TRISB.2 = 0

TRISB.3 = 0 ' 10k and 10k = 5k

case %11011000 ' AN3-270 --- 47k and 2.2k = 2.1k

TRISB.7 = 0 ' 47k and 15k = 11.3k

case %11101100 ' AN3-164 --- 100k and 22k = 18k

TRISB.5 = 0 '

TRISB.0 = 0 '

case %11110110 ' AN3-90

TRISB.5 = 0

TRISB.7 = 0

TRISB.3 = 0

end select

return

[mister_e]

Dunno buddy, replace your resistor with LED to Vdd and see what happen, Code seems to be OK.

On your PIC16F877, make sure you have all VDD and VSS pin connected, MCLR to VDD and the right capacitor around the crystal. If you're using an >4MHz one, set the HS_OSC fuse. Always make sure you also disable LVP in the configuration fuse too.

[mazoul72]

Dunno buddy , your program Code works very well with some resistors and one led on my PIC Hardware platform test .
With it , the intensity varies according to different buttons .
Perhaps microcode studio with 15 days trial .(compiler 3.0.0.1) ?
my programmer is willem with winpic800 .

[mazoul72]

i 've just try compiler 2.60 plus patch 2.60c under microcode studio 3.0.0.5
and verify fuse under willem (hs) , always the same .
arg , no understand why if the code is good .........................../

[mazoul72]

STUPID I AM , no pull-up resistors for RA2 and RA3....

[Ioannis]

Post #52

Ioannis

[mister_e]

----======----



----======----

[mazoul72]

Hello,

i tried with my car radio , it works well but a little slow for buttons reaction .
Perhaps the pause ...
I will try to integrate interrupts with it.
many thanks Steeve.

regards
Hervé

[mister_e]

Good news! The code itself should be fast enough, I guess the radio need some time to process it, and sure enough, it's not on his high priority task.

Post your code here, I'll check if I see something weird.

PS: when you post a code here use the code tags, this way it appear in a code box, and we don't miss the outdent format. It is really simple to do.
[code]
paste your code here
[/code]

[mazoul72]

Steeve ,

do you know where is the values for other functions like up/down/valid (press 2 or 3 seconds on function button) / EQ/Display ?
I have all general functions under 100kohms .
it is for DEH-6900IP Pioneer .

Thanks.

[mister_e]

Nope, sorry. Their service manual makes no mention of it, and the only thing I found was something like,
http://www.jvde.net/pioneer_wired_re...red_remote.htm

Even the original wired remote from Pioneer make no mention of this specific feature
http://www.pioneerelectronics.com/PU...ntrols/CD-MR70

[mazoul72]

Do the diode zener serve to fix no Function if i have no +12V on input regulator ?
Because when i put off +12V , i have a loop function (again and again.....)