wave_demo0.py

# "output" a waveform of a given length at a given frequency
import time
import math

# frequency in Hz of wave
frequency = 3

# length of the wave, number of samples in the wave
LENGTH = 13

# sine wave values written to the DAC
sin_wave = [
    int(math.sin(math.pi * 2 * i / LENGTH) * ((2**15) - 1) + 2**15)
    for i in range(LENGTH)
]

print(sin_wave)

wave_index = 0  # where in the wave we're at
wave_sleep = 1 / (frequency * LENGTH)  # how long to sleep between wave samples

print("wave_sleep:", wave_sleep)
time.sleep(1)

while True:
    print( "%5d %d" % (sin_wave[wave_index], wave_index) )
    wave_index = (wave_index + 1) % LENGTH
    time.sleep( wave_sleep )

wave_demo1.py

# "output" a waveform of a given length at a given frequency
# with the ability to change its frequency easily with asyncio

import asyncio
import time
import math

# frequency in Hz of wave
frequency = 5

# length of the sine wave
LENGTH = 13

# sine wave values written to the DAC
sin_wave = [
    int(math.sin(math.pi * 2 * i / LENGTH) * ((2**15) - 1) + 2**15)
    for i in range(LENGTH)
]
print(sin_wave)

async def wave_player():
    wave_index = 0
    while True:
        wave_sleep = 1/(frequency * LENGTH)
        print( "%5d %2d %f" % (sin_wave[wave_index], wave_index, wave_sleep) )
        wave_index = (wave_index + 1) % LENGTH
        await asyncio.sleep( wave_sleep )

async def frequency_changer():
    global frequency  # we change this, so must declare it
    while True:
        frequency = 5
        print("changing frequency to ", frequency)
        await asyncio.sleep( 5 )
        frequency = 0.3
        print("changing frequency to ", frequency)
        await asyncio.sleep( 5 )

async def main():
    task1 = asyncio.create_task( wave_player() )
    task2 = asyncio.create_task( frequency_changer() )
    await asyncio.gather(task1,task2)

asyncio.run(main())