NOT SAW

; NOT SAW reference. A counter starts at the per-case offset (input[0]) and climbs
; by the per-case step (input[1]); inverting it before the DAC turns the rising count
; into a falling saw. The seeds are read from the input, so one firmware draws all.
        mov  r2, 0
        ldb  r0, [r2]      ; r0 = counter start offset (input[0])
        mov  r2, 1
        ldb  r4, [r2]      ; r4 = ramp step (input[1])
loop:
        mov  r1, r0
        not  r1            ; invert: rising count becomes a falling saw
        out  p0, r1
        slp  1
        add  r0, r4        ; climb by the per-case step
        jmp  loop

# NOT SAW. ACT 4. SCOPE waveform board.
# TITLE NOT SAW
# OBJECTIVE A counter is inverted before output, making a falling saw.
# The battery moves the ramp step and the counter start offset, seeded into the
# input, so a captured transcript of one falling saw diverges on the next: only a
# firmware that reads the seed and inverts the running counter locks every case.
ID sc_a4_05_not_saw
WINDOW 64
DIR p0 OUT
PERIPH DAC data=p0 label=DAC_p0
CHAN p0 ANALOG label=CH1_p0_DAC
CASE phase=0 k=8
INPUT addr=0 label=START
INPUT addr=1 label=STEP
PAR power=520 lines=11 chips=1