PIC assembly code not working, PICKit2, ultrasonic sensor

Question

I am trying to mess around with some electronics, and like it so far! Got a PICKit 2 with a PIC16f1824 to code on. And i got myself a breadboard, with some leds, wires and a ultrasonic sensor. The sensor has 2 pins, 1 for trigger, and 1 for echo. This is my assembly code, but it does not work. The red led does not light up, at all :S

The breadboard is working and all is connected correctly, as far as i can tell. I have tested with simply turning on and off leds.

#include 

CBLOCK 0x70 ; DEFINE VARIABLES USED
d1
d2
d3
d4
Count
ENDC

ORG 0x00     ;RESET VECTOR

BANKSEL TRISA
movlw b'00000010' ;Setting all but RA1 to output, RA1 is input
movwf TRISA

MAINLOOP
CALL TRIG ;short burst to trigger pin
GOTO COUNT ;cout untill a signal is received
MLOOP
GOTO COUNTCHECK ;RA1, or echo, receives a signal, check how far
GOTO MAINLOOP

TRIG
CLRF Count
BANKSEL LATA
BSF LATA,0 ;trigger signal on
CALL Delay
BCF LATA,0 ;trigger signal off
RETURN

COUNT
INCF Count,1 ;increase by 1
CALL Delay ;delay 0.001 seconds
BANKSEL PORTA
BTFSS PORTA,1 ;checking if RA1 has recevied anything
GOTO COUNT ;loops
GOTO MLOOP ;RA1 received, go to main loop middle

COUNTCHECK
movlw d'6' ;gives w a value of 6
;movf Count,w ;
subwf Count,w ;count - w
BTFSC STATUS,C ;cheking c, is anything borrowed from w(nagative result) C is 0, nothing borrowed C is 1
;if result is 0, Z is 1(set), negative or positive is 0(clear)
GOTO REDLED ;turn on red led, Count is less than w(6) which means the obstacle is 1 meter away
GOTO GREENLED ;Count is larger than w(6), took more than 0.6 seconds before echo return, which means more than 1 meter away

REDLED
BANKSEL LATA
BCF LATA,3 ;turn off red led
BSF LATA,2 ;turn on green led
GOTO MAINLOOP ;go back to main loop, new trigger

GREENLED
BANKSEL LATA
BCF LATA,2 ;turn off green led
BSF LATA,3 ;turn on red led
GOTO MAINLOOP ;go back to main loop, new trigger

Delay       ;1 millisecond, 0.001 seconds
            ;993 cycles
    movlw   0xC6
    movwf   d1
    movlw   0x01
    movwf   d2
Delay_0
    decfsz  d1, f
    goto    $+2
    decfsz  d2, f
    goto    Delay_0

            ;3 cycles
    goto    $+1
    nop

            ;4 cycles (including call)
    return

END

kirill kirill · Accepted Answer · 2014-06-30T15:53:41

I suggest you to start with modifiing the example codes. Here is the link: http://www.microchip.com/DevelopmentTools/ProductDetails.aspx?PartNO=dm164130-9 There is a link "PICkit 3 Starter Kit Source Code" with a lot of examples in assembler and C.

PIC assembly code not working, PICKit2, ultrasonic sensor

2 Answers