CircuitPython driver for ES8311 I2S audio codec
A debt of gratitued is owed to @pschatzmann for arduino-audio-driver and arduino-audio-tools
circuitpython_es8311.py - minimal i2s audio driver for es8311 codec
* line in/mic input not supported
* Currently no way to run es8311 in "Master" mode
* MCLK must be derived from SCLK
* Currently no way to utilize inverted clock signals (MCLK/SCLK)
adafruit_tlv320.py - Shell library to allow applications written to use the TLV320 I2S DAC chip to run on boards using the ES8311 chip without modification (assuming the above limitations of circuitpython_es8311.py don't apply).
The Olimex RP2350pc board has a GPIO pin connected to the ES8311 power enable pin (GPIO22). This pin must be enabled for output and a True (1) value placed on the pin for the DAC to be powered. In addition, the speaker connectors are run through an on-board amplifier for which there is a Volume pin (GPIO34) and an Amplifer shutdown pin (GPIO35). In order for audio to play over the speaker connection the Volume pin must have a True (1) value and the Shutdown pin must have a False (0) value. The headphone jack will operate regardless of the Volume and Shutdown pin status, however inserting a headphone jack will cause the amplifer to shutdown turning off the speaker output.
Olimex RP2340pc Mini-Speaker
::
import board
import audiobusio
import audiocore
import digitalio
from circuitpython_es8311 import ES8311
pwr = digitalio.DigitalInOut(board.I2S_PWR)
pwr.direction=digitalio.Direction.OUTPUT
pwr.value=True
vol = digitalio.DigitalInOut(board.AMP_VOL)
vol.direction=digitalio.Direction.OUTPUT
vol.value=True
shdn = digitalio.DigitalInOut(board.AMP_SHDN)
shdn.direction=digitalio.Direction.OUTPUT
shdn.value=False
i2c = board.I2C()
dac = ES8311(i2c)
dac.configure_clocks(sample_rate=44100, bit_depth=16)
f = open('/sd/new.wav','rb')
wav = audiocore.WaveFile(f)
audio_bus = audiobusio.I2SOut(board.I2S_BCLK, board.I2S_WS, board.I2S_DIN)
audio_bus.play(wav)
print(audio_bus.playing)
(Olimex_RP2350pc_Beta_CP10.x.zip)
The RP2350pc has a 4 port USB hub connected in parallel to the USB device port which prevents the HUB from being used at the same time as the USB device (CIRCUITPY drive) in CircuitPython. This makes it a little more difficult to transfer files/programs to the internal flash of the device, however a standard FTDI to serial (or similar) cable can be connected to UEXT1 pins 2(GND), 3(GPIO0-TX) and 4(GPIO1-RX) over which Circuit Python will provide a serial REPL interface. Once this serial connection has been made to a host computer, Thonny or other microcontroller IDEs can be used to transfer files and run programs. In addition, CircuitPython will auto-mount any insrted SD card which can be used to transfer files as well.
Another possible option would be to flash the RP2350pc with Adafruit Feather RP2350 firmware from circuitpython.org. Using the Feather firmware the RP2350 peripherals will not work, however it will mount a CIRCUITPY drive. You can then copy the files you want on the internal flash and re-flash with the RP2350pc firmware at which point you should be able to interact with the REPL over the HDMI display and a keyboard plugged in to a USB hub port. If one of the files you placed on the internal flash in this manner was PyDOS (only the PyDOS.py file itself is required) then it will be trivial to move future files back and forth between inserted SD cards.