"""P9-5 Generate a sine wave using MCP4725 on I2C Bus"""
import math
from machine import Pin, I2C

i2c = I2C(1, scl = Pin(27), sda = Pin(26), freq = 400_000)

DEV_ADDR = 0x60
WAVEFORM_LENGTH = 360

# construct a data table for a sine wave
RADIAN = ((2 * math.pi) / WAVEFORM_LENGTH)
sinewave = []
for i in range(0, WAVEFORM_LENGTH):
    d = int(2047 * (math.sin(RADIAN * i) + 1))
    sinewave.append(d)


while True:
    for d in sinewave:
        # Create a bytearray of DAC command, high byte (D11-D4), low byte (D3-D0)
        ba = bytearray([0x40, (d >> 4) & 0xFF, (d << 4) & 0xF0])
        # Write the bytearray to MCP4725 DAC through I2C
        i2c.writeto(DEV_ADDR, ba)