Voicy's buggy project

[Voicy]

The Code

I made use of Assembler to code the 16F84. For those of you not familiar with it (Different to 'assembly' language) it's basically low level programming one up from binary entries.

Things to take into consideration was obviously coding space, but on an electronic level you have to account for "switch "de-bouncing" and "Antennae".

Switch de-bouncing is when you press the switch and the controller registers multiple presses. This is because the controller runs at 4micro seconds per instruction, so if you press the switch once (for 100ms at the shortest), the controller could register that as 25,000 presses.

That's why you need to switch off the input-reader for around 150ms after each button has been pressed in order to register it as a single press. The human finger can't press a switch faster than that, so it's a safe buffer to distinguish between multiple presses.

Antennae are metallic objects that pic up radio waves and even something as small as a leg (pin) on an IC that isn't grounded or set to +5V can pick up radio waves and the controller can falsely interpret it as an input signal.

Therefore, everytime an input is not required, you need to ground the pin by assigning a 0V to it avoid having the pin affect pins around it that are being used as inputs, thereby eliminating floating points.

For those interested, this is what the assembler code looks like for the buggy:

The first section is not so much creating variables as it is renaming ports and registers to something more understandable than just its number.

; ====== symbol setup ============


        STATUS        EQU            03
        OPT        EQU            01
        RPO        EQU            05
        PORTA        EQU            05
        TRISA        EQU            05
        PORTB        EQU            06
        TRISB        EQU            06
        RBPU        EQU            07
        ZFLAG        EQU            02
        rightsensor     EQU            04
        leftsensor    EQU            05
        frontsensor    EQU            06
        STRTBTN        EQU            07
        DelayL        EQU            0C                
        DelayM        EQU            0D                
        DelayH        EQU            0E    
        RecHits        EQU            0F        


; ====== port setup ============


START               BSF        STATUS,RPO
                    CLRF        TRISA                ; port a = outputs
                MOVLW        B'11110000'
                MOVWF        TRISB                ; rb4-rb7 = input, rb0 - rb3 = output
                    BCF         OPT,RBPU            ; enable pull ups
                BCF            STATUS,RPO


anfang                NOP    
                CLRF        PORTA                ; initialize ports
                CLRF         PORTB
                CLRF        RecHits                ; clear recorded hits by sensors


                CALL        Delay2000
STRTLP                BTFSC           PORTB,STRTBTN        ; waits for activate button to begin...
                    GOTO            STRTLP
                GOTO        BEGIN                
                
BEGIN               CALL        Delay2000            ; x4 = 2sec delay after start button pushed.


resume                NOP
                CALL        run
                GOTO        anfang

     
;======== 500 ms delay loop=====


DELAY500            CLRF        DelayL
                CLRF        DelayM
                MOVLW        H'1'            ;Fixed delay entry point
                MOVWF        DelayH            ;Variable Delay Entry point
LOOPD                DECFSZ        DelayL
                GOTO        LOOPD            ;returns to loop while counter > 0
                DECFSZ        DelayM
                GOTO        LOOPD
                DECFSZ        DelayH
                GOTO        LOOPD


    RETURN                                    ; return to program

;======= fwd =====


fwd                 MOVLW        B'1001'
                MOVWF        PORTA
                MOVWF        PORTB
                CALL        DELAY500
                BTFSS        PORTB,frontsensor
                BSF        RecHits,04
                BTFSS        PORTB,rightsensor
                BSF        RecHits,05
                BTFSS        PORTB,leftsensor
                BSF        RecHits,06


                BTFSC        RecHits,04
                GOTO        exitfwd
                BTFSC        RecHits,05
                GOTO        exitfwd
                BTFSC        RecHits,06
                GOTO        exitfwd
                
                MOVLW        B'1010'
                MOVWF        PORTA
                MOVWF        PORTB
                CALL        DELAY500
                BTFSS        PORTB,frontsensor
                BSF        RecHits,04
                BTFSS        PORTB,rightsensor
                BSF        RecHits,05
                BTFSS        PORTB,leftsensor
                BSF        RecHits,06


                BTFSC        RecHits,04
                GOTO        exitfwd
                BTFSC        RecHits,05
                GOTO        exitfwd
                BTFSC        RecHits,06
                GOTO        exitfwd
                MOVLW        B'0110'
                MOVWF        PORTA
                MOVWF        PORTB
                CALL        DELAY500
                BTFSS        PORTB,frontsensor
                BSF        RecHits,04
                BTFSS        PORTB,rightsensor
                BSF        RecHits,05
                BTFSS        PORTB,leftsensor
                BSF        RecHits,06


                BTFSC        RecHits,04
                GOTO        exitfwd
                BTFSC        RecHits,05
                GOTO        exitfwd
                BTFSC        RecHits,06
                GOTO        exitfwd


                MOVLW        B'0101'
                MOVWF        PORTA
                MOVWF        PORTB
                CALL        DELAY500
                BTFSS        PORTB,frontsensor
                BSF        RecHits,04
                BTFSS        PORTB,rightsensor
                BSF        RecHits,05
                BTFSS        PORTB,leftsensor
                BSF        RecHits,06


exitfwd                MOVLW        B'1001'
                MOVWF        PORTA
                MOVWF        PORTB
                
    RETURN


left                MOVLW        B'1001'
                MOVWF        PORTA
                MOVLW        B'1001'
                MOVWF        PORTB
                CALL        DELAY500

                MOVLW        B'0101'
                MOVWF        PORTA
                MOVLW        B'1010'
                MOVWF        PORTB
                CALL        DELAY500

                MOVLW        B'0110'
                MOVWF        PORTA
                MOVLW        B'0110'
                MOVWF        PORTB
                CALL        DELAY500

                MOVLW        B'1010'
                MOVWF        PORTA
                MOVLW        B'0101'
                MOVWF        PORTB
                CALL        DELAY500

                 MOVLW        B'1001'
                MOVWF        PORTA
                MOVLW        B'1001'
                MOVWF        PORTB


    RETURN

adjusta                MOVLW        B'1001'                ; move left wheel backwards
                MOVWF        PORTA
                CALL        DELAY500

                MOVLW        B'0101'
                MOVWF        PORTA
                CALL        DELAY500

                MOVLW        B'0110'
                MOVWF        PORTA
                CALL        DELAY500

                MOVLW        B'1010'
                MOVWF        PORTA
                CALL        DELAY500


                MOVLW        B'1001'
                MOVWF        PORTA
                
    RETURN

 circleleft            CALL        adjusta
                CALL        left
                CALL        left
                CALL        left
                BSF        RecHits,01            ; record bump to trigger right turn on next bump
                CALL        fwd
                BTFSC        RecHits,04            ; test if bumping front
                RETURN
                CALL        fwd
                BTFSC        RecHits,04
                RETURN
                CALL        fwd
                BTFSC        RecHits,04
                RETURN
                CALL        fwd
                BTFSC        RecHits,04
                RETURN
                CALL        fwd
                BCF        RecHits,01            ; recording of bump cleared, next turn left, not right on bump.
    
    RETURN

  adjustleft            CALL        back
                CALL        adjustb
    RETURN

run                CALL        fwd
                CALL        align
                BCF        RecHits,05
                BCF        RecHits,06
                BTFSS        RecHits,04
                goto        run
                BCF        RecHits,04
                BTFSS        RecHits,01
                CALL        circleleft
                BCF        RecHits,04
                BTFSS        RecHits,01
                GOTO        run
                CALL        circleright
                GOTO        run

     RETURN

    END

EDIT: I removed half of the code due to the 10,000 char limit per post ... but the essentials of how it works is in tact.