New approach to Rotary Encoder

[fratello]

This is schematic and code...Maybe I miss something important ...

@ DEVICE pic16F628A, XT_OSC, WDT_OFF, PWRT_ON, BOD_OFF, MCLR_ON, LVP_OFF, PROTECT_ON

include "alldigital.pbp"
   Define   OSC 4           ' 4MHz 
   CMCON = 7                ' Disable on-chip comparator, PORTA in digital mode


TrisA = %00011100           ; coloane la RA2, 3, 4 ; randuri la RA1, 0 ,7 
porta = %00011100
TRISB = %00000000
PORTB = %00010000 

oldState VAR BYTE
newState VAR BYTE

UP CON 1
DN CON 0


loop:
    PortA.1 = 0
    newState = PortA & %00011100         ; this is for my hw : 11100 = 28
    PortA.1 = 1

    If newState <> 28 THEN
        If newState <> oldState THEN
              
            Select Case oldState
                Case 12
                If NewState = 20 THEN dir=up       
                If NewState = 24 THEn dir=dn
                
                Case 20
                If NewState = 24 THEN dir=up               
                If NewState = 12 THEN dir=dn
               
                Case 24
                If NewState = 12 THEN dir=up                       
                If NewState = 20 THEN dir=dn
            END SELECT
            oldState = newstate
            GOSUB UpOrDn 
       pause 15                    ; time for UpOrDn     
       endif          
    ENDIF
;============
UpOrDn:
if dir=DN then
    PortB.4 = 0
    pauseus 3850
    PortB.4 = 1
    pauseus 3850
    PortB.4 = 0
    pauseus 660
    PortB.4 = 1
endif

if dir=UP then
    PortB.4 = 0
    pauseus 4450
    PortB.4 = 1
    pauseus 4400
    PortB.4 = 0
    pauseus 660
    PortB.4 = 1
endif    
return

end

[HenrikOlsson]

1) I don't understand why you keep putting those PAUSE statements in there, now you have a PAUSE 15 in there....
2) There's no GOTO LOOP anywhere so the program will "fall thru" into the UpOrDn routine then hit the RETURN and bad things will happpen. (BTW, Loop is a reserved word in newer versions of PBP, best to get used to not using it.
3) Try resampling the pins and set oldState when you return from the subroutine, ie (changes in red):

Main:
    PortA.1 = 0
    newState = PortA & %00011100         ; this is for my hw : 11100 = 28
    PortA.1 = 1
    If newState <> 28 THEN
        If newState <> oldState THEN
              
            Select Case oldState
                Case 12
                If NewState = 20 THEN dir=up       
                If NewState = 24 THEn dir=dn
                
                Case 20
                If NewState = 24 THEN dir=up               
                If NewState = 12 THEN dir=dn
               
                Case 24
                If NewState = 12 THEN dir=up                       
                If NewState = 20 THEN dir=dn
            END SELECT
            GOSUB UpOrDn 
            
            PAUSE 15                    ; time for UpOrDn   
         
     ' Now resample the encoder and keep the state as oldState
          PortA.1 = 0
         oldState = PortA & %00011100         ; this is for my hw : 11100 = 28
         PortA.1 = 1     
       
    ENDIF          
  ENDIF
GOTO MAIN
;============
UpOrDn:
if dir=DN then
    PortB.4 = 0
    pauseus 3850
    PortB.4 = 1
    pauseus 3850
    PortB.4 = 0
    pauseus 660
    PortB.4 = 1
endif
if dir=UP then
    PortB.4 = 0
    pauseus 4450
    PortB.4 = 1
    pauseus 4400
    PortB.4 = 0
    pauseus 660
    PortB.4 = 1
endif    
RETURN
END

[fratello]

Mr. Henrik I must get my hat in front of you ! (Hope G.translate work well !).
NOW, the code work verry good !!! Only sometimes the command are inversed , but in 9 case of 10 it's ok, so I can live with this...
Thanks for lost so much time with me ! I am verry grateful !

[HenrikOlsson]

Great, finally... Now try removing the PAUSE 15 and see if that improves it further.

[fratello]

Thanks to Mr.Henrik Olsson this code work PERFECT !!! I'm sure I would not have done it without his help !

Main:
    PortA.1 = 0
    newState = PortA & 011100        
    PortA.1 = 1

    If newState <> 28 THEN
        If newState <> oldState THEN
              
            Select Case oldState
                Case 12
                If NewState = 20 THEN dir=up       
                If NewState = 24 THEn dir=dn
                
                Case 20
                If NewState = 24 THEN dir=up               
                If NewState = 12 THEN dir=dn
               
                Case 24
                If NewState = 12 THEN dir=up                       
                If NewState = 20 THEN dir=dn
            END SELECT

            GOSUB UpOrDn 

    PortA.1 = 0
    OldState = PortA & 011100         
    PortA.1 = 1
               
       endif          
    ENDIF
Goto Main

[kzeoprf]

Hi to all. I want to use a rotary encoder with a 18f252, and i have a lot of troubles. I want to use interupts, so my only solution PORTB or I can use Portc also?

I made a pcb and I made the connections to PORTC, and I also use a debounce circuit, which I think causes problems. Anyone has a snipset code cause I do not have any expieriance with encoders?
5v
__|__
| |
/ /
\ \
/10k / 10K
\ \
| A | B ENC
- -
| |-------------------------------
\ |
/10K \
\ /10K
/ \
|--------------------- |--------------------
PORTC.2 | PORTC.3 |
---- ----- 100nF
---- -----
| |
--------- -----------
----- -----
- -

[HenrikOlsson]

Hello,
On the 18F252 there's no interrupt capabillity on PortC.

Your schematic really doesn't show up that good here but it LOOKS like you have a 10k from 5V to the "top" of each of the switches in the encoders, then the other side of each switch thru another 10k to the input with a 100nF cap to GND, is that correct?

If the above is not correct please post a proper schematic for us to see.
If the above IS correct then it's not a very good hardware design IMHO. When the switch in the ecoder is closed you have 2*10k in series to the input, decoupled by a 100nF cap, this may be fine. But when the switch is open there's no path for the capacitor to discharge except thru the fairly high input impedance of the pin. In effect the pin floats which is not a good thing for inputs.

/Henrik.