led.asm

#include <xc.inc>

#define STRIP_LENGTH 10
#define LED_STRIP PORTA, 0

GLOBAL _led_buffer

GLOBAL _populateLeds
PSECT ledcode,class=CODE,reloc=2
_populateLeds:
    BSF PIR1, 1 //Set the interrupt flag so that we pass through the initial wait loop without waiting

;    LFSR 0,_led_buffer //1
;    MOVF POSTINC0, 0 //1
;    BZ zeroresult
;    BSF PORTB, 5
;    RETURN
;
;zeroresult:
;    BCF PORTB, 5
;    RETURN

    LFSR 0,_led_buffer //1
    MOVF POSTINC0, 0 //1
    MOVWF RXB1D7 //1
startStrip:
    //CURRENT LED
    MOVLW 10//1
    MOVWF RXB1D4 //1

    //CURRENT COLOR COMPONENT
    MOVLW  3//1
    MOVWF RXB1D5 //1

    //CURRENT BIT
    MOVLW  8//1
    MOVWF RXB1D6 //1

timerWaitLoop2:
    BTFSS PIR1, 1 //1, 2 or 3
    BRA timerWaitLoop2

    BSF LED_STRIP ///////////////////////////////////////////////// SET

    //clear timer overflow (timer trips again in 20 cycles)
    BCF PIR1, 1 //1

    //bit shift and set carry flag
    RLCF RXB1D7, 1, 0 //1
    //BRA transmitOne
    //BC transmitOne //1 or 2
    NOP

transmitZero:
    BCF LED_STRIP///////////////////////////////////////////////// CLEAR

    //Decrement current bit, jump if nonzero
    DECF RXB1D6, 1 //1
    BNZ timerWaitLoop2

    //load a new byte into memory
    MOVF POSTINC0, 0 //1
    MOVWF RXB1D7 //1

    //CURRENT BIT
    MOVLW  8//1
    MOVWF RXB1D6 //1

    //Decrement component count
    DECF RXB1D5, 1 //1
    BNZ timerWaitLoop2

    MOVLW  3//1
    MOVWF RXB1D5 //1

    //Decrement LED count
    DECF RXB1D4, 1 //1
    BNZ timerWaitLoop2

    BRA done
transmitOne:
    //we have a maximum of 5 cycles here
    //count NOPs
    NOP
    NOP
    NOP
    NOP
    NOP

    BCF LED_STRIP ///////////////////////////////////////////////// CLEAR

    //Decrement current bit, jump if nonzero
    DECF RXB1D6, 1 //1
    BNZ timerWaitLoop2

    //load a new byte into memory
    MOVF POSTINC0, 0 //1
    //MOVLW  10//1
    MOVWF RXB1D7 //1

    //CURRENT BIT
    MOVLW  8//1
    MOVWF RXB1D6 //1

    //decrement component count
    DECF RXB1D5, 1 //1
    BNZ timerWaitLoop2

    MOVLW  3//1
    MOVWF RXB1D5 //1

    //decrement LED count
    DECF RXB1D4, 1 //1
    BNZ timerWaitLoop2

done:

//################### ASM RESET ##############
// sents a reset to the LED strip