Stable ADC readings

[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

[karlos]

Hello Mazoul72
I think that you will be the one who can help me in this particulary issue. With all the respect for the experts of this great forum, but most of the users use so tecnical language that i don't understand. My formation is in philosophy...
Behind my radio i have the k line, althrought my car is not can bus. As far as i understand the communications protocol is 3LB.
Some months ago i've bought all the wiring for the multifunction steering wheel of the golf4, the relay 452 and the buttons (left and right). But i'm trying to make more buttons enable, because on the Golf4 MFSW there are only 4 buttons for control the radio and 3 buttons for cruise control. At least i would like to have six buttons to radio (volume up and volume down, next and previous track, next and previous source).
I'm very frustrated because it all remain the same and i have a gorgeous multifunction steering wheel without functions...
Perhaps you are kindness and maybe you could make one interface for me. If you want so, i can send you the money for the materias. I don't mind to take a change and i feel that i can trust you.

Regards
Karlos

[mazoul72]

I think it is more reliable to use Kline to access to all functions (i am going to try to use these adresses Kline functions)
i have a code but i have to work on it (Kline access based) .i will give a part of it in a new post to hope that someone can help us about it .
Because my FIS display base code is the same than Golfop...(take on a yahoo group FREELY and freely redistriable but now it is too expensive to buy it---lot of work on it) .
For try it , we have to use a little program to send caracters between DB25// and K-line .(see logs) LOGS.zip

[mazoul72]

EDIT :

See logs for what reacts FIS with sent caracters ... Attachment 6112

LineK schematics , but we need a program to send values to see how reacts car radio LineK wire ...

code :

data(data line),clk(clock)
suma=0
dat=126
Shiftout data, clk, 5,[dat]
suma=suma ^ dat

Rem High data

dat=237
Shiftout dato, clk, 5,[dat]
suma=suma ^ dat

Rem Low data

dat=15
Shiftout dato, clk, 5,[dat]
suma=suma ^ dat

Rem High data
It is for DATA Line send (ENA/CLOCK/DATA)

For cont=0 To 15
tmp=msg[cont]
Rem dat=255 - tmp
dat= ~ tmp
suma=suma ^ dat
Shiftout data, clk, 5,[dat]
Rem Low data
Next cont

'Somme de controle (sum)

dat=suma + 1
Shiftout data, clk, 5,[dat]
Rem Low data
High ena
posy=255
GoSub display


FisDw:
Low ena
suma=0
dat=169
Shiftout data, clk, 5,[dat]
sum=sum ^ dat

know 255-longitude del msg

dat=241
Shiftout data, clk, 5,[dat]
sum=sum ^ dat

It is for example ,but it is a little part of sent values .

Thanks in advance to ameliorate or given answers .