#include <xc.inc>
#include <pic12f1840.inc>

    OPT LIST

GLOBAL _rgb_sample
GLOBAL _rgb_bit
GLOBAL _rgb_byte
GLOBAL _rgbdata

GLOBAL _ws2811_send

PSECT mytext,local,class=CODE,delta=2

; send the whole pile of data
_ws2811_send:
    ; copy the led colour array into FSR0 for fast access
    MOVLW _rgbdata >> 8
    MOVWF FSR0H
    MOVLW _rgbdata & 0xFF
    MOVWF FSR0L


    ; load next byte from array into working reg
ws2811_nextbyte:
    MOVIW FSR0++
    MOVWF _rgb_sample
    MOVLW 8             ; reset bit count
    MOVWF _rgb_bit

ws2811_sendbit:
    ; you assume its a zero then test if its one
    MOVLW 0xC0 ;11000000B
    RLF _rgb_sample,f
    BTFSC CARRY
    MOVLW 0xF8 ; 11111000B

;    // wait until the buffer is empty
;ws2811_waitsend:
;    BTFSC PIR1, 3
;    BRA ws2811_waitsend

    ; send the bit
    BANKSEL (SSP1BUF)
    MOVWF BANKMASK(SSP1BUF)

    ; any more bits
    DECFSZ _rgb_bit,f
    BRA ws2811_sendbit

    ; any more bytes
    DECFSZ _rgb_byte,f
    BRA ws2811_nextbyte

    ; all done
    RETURN