from machine import Pin
import utime
import math

pines = [2, 3, 4, 5, 6, 7, 8, 9, 10]

def GPIO_SALP(valor, listagpio):
    pines_gpio = [Pin(pin, Pin.OUT) for pin in listagpio]
    ii = 1
    for i in range(8):
        pines_gpio[i].value(1 if (valor & ii) else 0)
        ii = ii << 1

def SerieFourier_Ej2(nmax):
    """
    Funcion definida en [-2, 2) con periodo T = 4:

        f(x) =  0   para  -2 <= x < -1
        f(x) = -2   para  -1 <= x <  0
        f(x) =  1   para   0 <= x <  1
        f(x) =  0   para   1 <= x <  2

    Frecuencia angular fundamental: w0 = 2pi / T = pi/2

    Coeficientes (verificados termino a termino):
        a0 = -1/2

        an = -(1 / (n*pi)) * sin(n*pi/2)

        bn = (3 / (n*pi)) * (1 - cos(n*pi/2))

    Serie resultante:
        f(x) = a0/2 + SUM[ an*cos(n*w0*x) + bn*sin(n*w0*x) ]
             = -1/4  + SUM[ an*cos(n*pi/2*x) + bn*sin(n*pi/2*x) ]
    """

    T    = 4.0              # periodo real
    w0   = math.pi / 2.0   # frecuencia angular fundamental = 2pi/T = pi/2
    a0   = -0.5             # = -1/2

    xmin  = 0.0
    xmax  = T               # un periodo completo
    delta = T / 120.0       # 120 muestras por periodo

    x = xmin
    while x < xmax:
        sum_val = 0.0

        for n in range(1, nmax + 1):
            npi2  = n * math.pi / 2.0      # n*pi/2
            sin_h = math.sin(npi2)         # sin(n*pi/2)
            cos_h = math.cos(npi2)         # cos(n*pi/2)

            # --- Coeficiente an ---
            an = -(1.0 / (n * math.pi)) * sin_h

            # --- Coeficiente bn ---
            bn = (3.0 / (n * math.pi)) * (1.0 - cos_h)

            sum_val += an * math.cos(n * w0 * x) + bn * math.sin(n * w0 * x)

        fx = a0 / 2.0 + sum_val   # = -1/4 + suma armonicos
        print(fx)

        # --- Mapeo a 8 bits ---
        # Rango de f(x): [-2, 1]  -> se mapea a [0, 255]
        f_min = -2.5
        f_max =  1.5
        val_dac = int((fx - f_min) / (f_max - f_min) * 255.0)
        val_dac = max(0, min(255, val_dac))
        GPIO_SALP(val_dac, pines)

        x += delta

# Bucle principal: barre el numero de armonicos de 1 a 49
while True:
    for narmonicos in range(1, 50, 1):
        SerieFourier_Ej2(narmonicos)