.include "ATxmega128A1Udef.inc"

.EQU    stack_init = 0x2FFF ;initialize stack pointer (between 0x2000 & 0x3FFF)
                            ;  Default is 0x3FFF

.equ    eot = 0x09  ;0x09, 0x10
.ORG 0x7800
pattern:    .DB 0x01,0x03,0x06,0x0c,0x18,0x30,0x60, 0xC0, 0x80; , 0xC0, 0x60, 0x30, 0x18, 0x0c, 0x06, 0x03

.ORG 0x0000                 ;Code starts running from address 0x0000.
    rjmp MAIN               ;Relative jump to start of program.

.ORG 0x0100                 ;Start program at 0x0100 so we don't overwrite
                            ;  vectors that are at 0x0000-0x00FD
MAIN:

    ;initialize stack pointer
    ldi YL, low(stack_init)
    out CPU_SPL, YL
    ldi YH, high(stack_init)
    out CPU_SPH, YH

    ;initialize pattern list
    ldi ZL, low(pattern<<1)
    ldi ZH, high(pattern<<1)

    ldi R16, 0xFF           ;load a 8bit high
    sts PORTC_DIRSET, R16   ;set all the GPIO's in the 8 bits PORTD as outputs

    ldi R17, 0xFF           ; hold current pattern symbol

LOOP:
    ;end of the table, reset pointer
    cpi ZL, eot
    brsh reset_z

    lpm r17, Z+

    push r16
    ldi r16, 5      ;50ms delay
    rcall DELAY_x10ms
    pop r16

    com R17         ;complement bits for active-low
    sts PORTC_OUT, R17 ; turn on

    push r16
    ldi r16, 5      ;50ms delay
    rcall DELAY_x10ms
    pop r16

    com R17
    sts PORTC_OUT, R17  ; turn off

    rjmp LOOP
reset_z:
    ldi ZL, low(pattern<<1)
    ldi ZH, high(pattern<<1)
    rjmp LOOP               ;repeat forever!


/****************************************
 * Subroutine DELAY_x10ms loops until desired delay is reached
 * Inputs:  R16 (=N), the millisecond multiplier
 *
 * Outputs:  return to caller
 * Affected: R16 will be 0 upon return
 **************************************/
DELAY_x10ms:
    push r31
    push r30

    DELAY_10ms:
        ldi r31, 17     ; 9 x 1020 = approx 10,000 x.5 microsecons/instr = 10millseconds
        outer:
            dec r31
            cpi r31, 0
            breq done_10ms
            ldi r30, 254    ;255 x4 = 1020 cycles
            inner:
                cpi r30, 0
                breq outer
                dec r30
                rjmp inner
    done_10ms:
        dec r16
        cpi r16, 0
        breq done_x10ms
        rjmp DELAY_10ms

done_x10ms:
    pop r30
    pop r31
    ret