New approach to Rotary Encoder

[aratti]

Here the code for a rotary optical encoder, using quadrature.
Just connect the Channel A to portB.6 and channel B to portB.7, ground portB.5 and portB.4

Connection for LCD can be found to page 96 of PBP user manual.

include "ALLDIGITAL.pbp"
INCLUDE "DT_INTS-14.bas"        ; Base Interrupt System
'INCLUDE "ReEnterPBP.bas"        ; Include if using PBP interrupts

DEFINE OSC 20

'                       PIC 16F628
' PicBasic program to demonstrate operation of an LCD in 4-bit mode
'          and reading an optical encoder in quadrature
'
' LCD should be connected as follows:
'       LCD     PIC
'       DB4     PortA.0
'       DB5     PortA.1
'       DB6     PortA.2
'       DB7     PortA.3
'       RS      PortA.4 (add 4.7K pullup resistor to 5 volts)
'       E       PortB.0
'       RW      Ground
'       Vdd     5 volts
'       Vss     Ground
'       Vo      20K potentiometer (or ground)
'       DB0-3   No connect


TrisA = 000000
TrisB = 110000
PortB=0

Define LCD_DREG PORTA
Define LCD_DBIT 0
Define LCD_RSREG PORTA
define LCD_RSBIT 4
define LCD_EREG PORTB
define LCD_EBIT 0
define LCD_BITS 4
define LCD_LINES 2
define LCD_COMMANDUS 2000
define LCD_DATAUS 50

Flag                var bit
wsave               VAR BYTE    $70     SYSTEM  ' alternate save location for W 
Q_New               var Byte
Q_Old               var byte
Q_Count             var word


' Set variable value @ startup
          Flag = 0          
         Q_New = 0
         Q_Old = 0
       Q_Count = 0

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, Resetflag?
        INT_Handler    RBC_INT,  _Encoder,   ASM,  yes
    endm
    INT_CREATE                      ; Creates the interrupt processor
ENDASM

@ INT_ENABLE RBC_INT            ; enable external (INT) interrupts


Lcdout $fe, 1                       ' Clear LCD screen
Lcdout "System Ready"               ' Display message
Pause 500                           ' Wait .5 second

Goto Main_Loop

Encoder:
Q_New = PortB.7 + PortB.7 + PortB.6

if Q_Old = 0 then
if Q_New = 2 then Minus_Count
if Q_New = 1 then Plus_Count
endif

if Q_Old = 1 then
if Q_New = 0 then Minus_Count
if Q_New = 3 then Plus_Count
endif

if Q_Old = 3 then
if Q_New = 1 then Minus_Count
if Q_New = 2 then Plus_Count
endif

if Q_Old = 2 then
if Q_New = 3 then Minus_Count
if Q_New = 0 then Plus_Count
endif

goto Q_Skip

Minus_Count:
Q_Count = Q_Count - 1
   Flag = 1
goto Q_Skip

Plus_Count:
Q_Count = Q_Count + 1
   Flag = 1
Q_Skip:
Q_Old = Q_New
 
 
@ INT_RETURN

Main_Loop:   

if Flag = 1 then
Lcdout $fe, 1                    
Lcdout Dec Q_Count
Flag = 0
endif

goto Main_Loop

end

Enjoy

Cheers

Al.

[Mike, K8LH]

Connection for LCD can be found to page 96 of PBP user manual.

Do you have a link the that manual, please? I've looked at two different PBP Compiler Manuals so far and neither has a schematic for an LCD interface on page 96...