how to read ky40 mechanical encoder ?

[iw2fvo]

I am sorry Richar for having posted the file that is not the final one:
please change the following:

A VAR PORTD.0 ' encoder A PHASE
shAll be:
A VAR PORTB.0

This is the interrupt input !

I would be happy to know ...
Thanks and regards,
Ambrogio

[iw2fvo]

I did capture the output of the terminal printout for a better check.
There are about 200 changes of the cnt obtained by "manually" turning the encoder knob on my control panel. Probably sometims cw and ccw.
I noted very few spikes : I am not shure if they are due to the time required for the serial port output or to the encoder software.
Any improvement to the program is very much appreciated.
I am really searching for a good solution.
Thanks
regards,
Ambrogio

[richard]

I do it this way

enc pins must be sequential and on same port
both enc pins must be able to generate an interrupt (ioc on neg and pos edge is best , ioc, rac,rbc on neg or pos edge will work as will int0 int1)
enc pins must be pulled up (10k) and have 0.1uF filter caps

I have an asm version that's 100 bytes smaller and has about 1 tenth of the irq latency and is much faster too

'****************************************************************
'*  Name    : rotary encoder.BAS                                *
'*  Author  : richard                                           *
'*  Notice  : Copyright (c) 2013                                *
'*          : All Rights Reserved                               *
'*  Date    : 9/4/2013                                          *
'*  Version : 1.0    16f1825                                    *
'*  Notes   :  enca porta.2 encb porta.3                        *
'*          :   note mclr disabled ,full quad decode            *
'****************************************************************
  
#CONFIG
             __config        _CONFIG1,    _FOSC_INTOSC & _CP_OFF & _WDTE_ON  &  _PWRTE_ON  &  _MCLRE_OFF  & _CLKOUTEN_OFF
              __config      _CONFIG2, _PLLEN_ON & _LVP_OFF
#ENDCONFIG
  
 
include "dt_ints-14.bas"
include "REENTERPBP.bas"
 
asm
INT_LIST macro
      INT_HANDLER IOC_INT, _enc_isr,pbp,NO
      endm
 INT_CREATE
ENDASM    
 
DEFINE OSC 32
 
 
 
 
   OSCCON=$70
   ANSELA=0
   
   OPTION_REG.6=0
 
   ev    VAR BYTE bank0
   cnt   VAR WORD bank0
   TMP   VAR BYTE bank0
   enca  VAR porta.2 
   encb  VAR porta.3
   TRISA = 111110
  
   lata.0=1
   IOCAP=12    ;enca porta.2 encb porta.3  pos edge trigger
   IOCAN=12    ;enca porta.2 encb porta.3  neg edge trigger
    
    
   pause 4000 
   
   serout2 PORTA.0,84,[ "ready",13,10]
   IOCAF=0
   
   INTCON=$C8
   
   
   
mainloop:  
 
 serout2 PORTA.0,84,[13,10, "C",#CNT]
 pause 1000
 
 goto mainloop
    
 
    
 
enc_isr:
    

ev=ev<<2              ;shift last reading into position
ev=ev|((porta&12)>>2)  ;read enc pins 2,3  mask off others then  combine this reading with last reading
LOOKUP (ev&$f),[0,255, 1, 0, 1, 0, 0, 255, 255, 0, 0, 1, 0, 1, 255, 0],tmp ;lookup the decision matrix
if tmp then         ; decide to inc , dec or ignore 
 if tmp.7 then
   cnt=cnt-1
 else
    cnt=cnt+1
 endif
endif
intcon.0=0                   ; clean up and exit
iocaf=0
@ INT_RETURN

[iw2fvo]

Thanks Richard for the code.
I am just a little bit busy on these days and so I plan to try your code on next days.
As you have seen I am using pic18f452: Is your code applicable to this micro ?
If no, what should I modify or adapt ?
Thanks
Regards,
Ambrogio

[richard]

for a pic18f452 you need to use RBC_INT for best results and pins portb.4,5 or portb.6,7 or portb.5,6

this line needs to match chosen p1ns

ev=ev|((porta&12)>>2) ;read enc pins 2,3 mask off others then combine this reading with last reading

for pins portb.4,5 it would be

ev=ev|((portb&48)>>4)

INT_LIST macro
      INT_HANDLER IOC_INT, _enc_isr,pbp,NO
      endm
 INT_CREATE

would be

INT_LIST macro
      INT_HANDLER RBC_INT, _enc_isr,pbp,NO
      endm
 INT_CREATE

IOCAP=12 ;enca porta.2 encb porta.3 pos edge trigger
IOCAN=12 ;enca porta.2 encb porta.3 neg edge trigger
IOCAF=0
INTCON=$C8

would be

dummy_var = portb
INTCON=$C8

any references to IOCAF need to be deleted , trisb must be appropiate

[iw2fvo]

Hi Richard,
I am going to modify my previous program with your indications.
Probably I did something wrong and it is not working.
I am attaching the full code : could you please have a look of it ?
Thanks again for the assistance
regards,
Ambro

[richard]

I would do it like this

'****************************************************************
'*  Name    : pic controlled power supply                       *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2015 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 11/09/2015                                        *
'*  Version : 1.0                                               *
'*  Notes   : pic18f452 10mhz x 4 pll = 40 MHZ                  *
'****************************************************************
';Program Configuration Register 1H
@  __CONFIG    _CONFIG1H, _OSCS_OFF_1H & _HSPLL_OSC_1H      
';Program Configuration Register 2L
@  __CONFIG    _CONFIG2L, _BOR_OFF_2L & _BORV_20_2L & _PWRT_ON_2L
';Program Configuration Register 2H
@  __CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_128_2H
';Program Configuration Register 3H
@  __CONFIG    _CONFIG3H, _CCP2MX_OFF_3H
';Program Configuration Register 4L
@  __CONFIG    _CONFIG4L, _STVR_OFF_4L & _LVP_OFF_4L & _DEBUG_OFF_4L
';Program Configuration Register 5L
@  __CONFIG    _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L & _CP2_OFF_5L & _CP3_OFF_5L 
';Program Configuration Register 5H
@  __CONFIG    _CONFIG5H, _CPB_OFF_5H & _CPD_OFF_5H
';Program Configuration Register 6L
@  __CONFIG    _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L & _WRT2_OFF_6L & _WRT3_OFF_6L 
';Program Configuration Register 6H
@  __CONFIG    _CONFIG6H, _WRTC_OFF_6H & _WRTB_OFF_6H & _WRTD_OFF_6H
';Program Configuration Register 7L
@  __CONFIG    _CONFIG7L, _EBTR0_OFF_7L & _EBTR1_OFF_7L & _EBTR2_OFF_7L & _EBTR3_OFF_7L
';Program Configuration Register 7H
@  __CONFIG    _CONFIG7H, _EBTRB_OFF_7H
' ***************************************************************************
 
DEFINE OSC 40                 ' XTAL= 10 MHZ   CLOCK= 40 MHZ
INCLUDE "MODEDEFS.BAS"
include "dt_ints-14.bas"
include "REENTERPBP.bas"
 

CNT VAR WORD                   ' COUNTER TO BE DISPLAYED ON TERMINAL
CNT= 32000
CNTOLD VAR WORD
CNTOLD=32000
counter VAR WORD
counter= 32000
' DEBUG INTERFACE  \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
'' Set Debug pin port   ________________________________________
DEFINE DEBUG_REG PORTD
'' Set Debug pin bit   _________________________________________ PIC_PIN_30
DEFINE DEBUG_BIT 7
'' Set Debug baud rate _________________________________________
DEFINE DEBUG_BAUD 115200
'' Set Debug mode: 0 = true, 1 = inverted ______________________
DEFINE DEBUG_MODE 1
DEBUG 13,10,13,10, " PROGRAM IS STARTING...", 13, 10, 13, 10                         
ADCON1=7                      ' all digital !
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    RBC_INT,  _enc_isr,   PBP,  NO
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

  
'@   INT_ENABLE   RBC_INT     ; enable external (INT) interrupts
   ev    VAR BYTE BANK0
   TMP   VAR BYTE BANK0
   enca  VAR portb.4 
   encb  VAR portb.5
   TRISA = 255
  
   lata.0=1
   tmp = portb  ;; read portb to establish pin change status
   INTCON=$C8  ; enable RBC_INT and clear rbcif
Main:
  PAUSE 1000
  gosub get_cnt:
  IF counter <> CNTOLD THEN
     DEBUG DEC CNT,13,10
     CNTOLD=counter  ENDIF
  
GOTO Main
enc_isr:
    
ev=ev<<2              ;shift last reading into position
ev=ev|((portb&48)>>4)  ;read enc pins 4+5  mask off others then  combine this reading with last reading
LOOKUP (ev&$f),[0,255, 1, 0, 1, 0, 0, 255, 255, 0, 0, 1, 0, 1, 255, 0],tmp ;lookup the decision matrix
if tmp then         ; decide to inc , dec or ignore 
 if tmp.7 then
   cnt=cnt-1
 else
    cnt=cnt+1
 endif
endif
intcon.0=0                   ; clean up and exit
@ INT_RETURN



get_cnt:       ;  cnt is not atomic   this is needed to avoid rollover miss reads
intcon.3=0
counter=cnt
intcon.3=1
return