analogbufio – Analog Buffered IO Hardware Support

The analogbufio module contains classes to provide access to analog-to-digital conversion and digital-to-analog (DAC) for multiple value transfer.

All classes change hardware state and should be deinitialized when they are no longer needed if the program continues after use. To do so, either call deinit() or use a context manager. See Lifetime and ContextManagers for more info.

TODO: For the essentials of analogbufio, see the CircuitPython Essentials Learn guide

TODO: For more information on using analogbufio, see this additional Learn guide

Available on these boards
  • 0xCB Helios
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class analogbufio.BufferedIn(pin: microcontroller.Pin, *, sample_rate: int)

Capture multiple analog voltage levels to the supplied buffer

Usage:

import board
import analogbufio
import array

length = 1000
mybuffer = array.array("H", [0x0000] * length)
rate = 500000
adcbuf = analogbufio.BufferedIn(board.GP26, sample_rate=rate)
adcbuf.readinto(mybuffer)
adcbuf.deinit()
for i in range(length):
    print(i, mybuffer[i])

(TODO) The reference voltage varies by platform so use
``reference_voltage`` to read the configured setting.
(TODO) Provide mechanism to read CPU Temperature.

Create a BufferedIn on the given pin and given sample rate.

Parameters:
  • pin (Pin) – the pin to read from

  • sample_rate (~int) – rate: sampling frequency, in samples per second

deinit() None

Shut down the BufferedIn and release the pin for other use.

__enter__() BufferedIn

No-op used by Context Managers.

__exit__() None

Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.

readinto(buffer: circuitpython_typing.WriteableBuffer) int

Fills the provided buffer with ADC voltage values.

ADC values will be read into the given buffer at the supplied sample_rate. Depending on the buffer typecode, ‘B’, ‘H’, samples are 8-bit byte-arrays or 16-bit half-words and are always unsigned. The ADC most significant bits of the ADC are kept. (See https://docs.circuitpython.org/en/latest/docs/library/array.html)

Parameters:

buffer (WriteableBuffer) – buffer: A buffer for samples