adafruit_bus_device.i2c_device
- I2C Bus Device¶
- class adafruit_bus_device.i2c_device.I2CDevice(i2c: I2C, device_address: int, probe: bool = True)[source]¶
Represents a single I2C device and manages locking the bus and the device address.
- Parameters
Note
This class is NOT built into CircuitPython. See here for install instructions.
Example:
import busio from board import * from adafruit_bus_device.i2c_device import I2CDevice with busio.I2C(SCL, SDA) as i2c: device = I2CDevice(i2c, 0x70) bytes_read = bytearray(4) with device: device.readinto(bytes_read) # A second transaction with device: device.write(bytes_read)
- readinto(buf: Union[array, bytearray, memoryview, rgbmatrix.RGBMatrix, ulab.numpy.ndarray], *, start: int = 0, end: Optional[int] = None) None [source]¶
Read into
buf
from the device. The number of bytes read will be the length ofbuf
.If
start
orend
is provided, then the buffer will be sliced as ifbuf[start:end]
. This will not cause an allocation likebuf[start:end]
will so it saves memory.
- write(buf: Union[array, bytearray, bytes, memoryview, rgbmatrix.RGBMatrix, ulab.numpy.ndarray], *, start: int = 0, end: Optional[int] = None) None [source]¶
Write the bytes from
buffer
to the device, then transmit a stop bit.If
start
orend
is provided, then the buffer will be sliced as ifbuffer[start:end]
. This will not cause an allocation likebuffer[start:end]
will so it saves memory.
- write_then_readinto(out_buffer: Union[array, bytearray, bytes, memoryview, rgbmatrix.RGBMatrix, ulab.numpy.ndarray], in_buffer: Union[array, bytearray, memoryview, rgbmatrix.RGBMatrix, ulab.numpy.ndarray], *, out_start: int = 0, out_end: Optional[int] = None, in_start: int = 0, in_end: Optional[int] = None) None [source]¶
Write the bytes from
out_buffer
to the device, then immediately reads intoin_buffer
from the device. The number of bytes read will be the length ofin_buffer
.If
out_start
orout_end
is provided, then the output buffer will be sliced as ifout_buffer[out_start:out_end]
. This will not cause an allocation likebuffer[out_start:out_end]
will so it saves memory.If
in_start
orin_end
is provided, then the input buffer will be sliced as ifin_buffer[in_start:in_end]
. This will not cause an allocation likein_buffer[in_start:in_end]
will so it saves memory.- Parameters
out_buffer (~ReadableBuffer) – buffer containing the bytes to write
in_buffer (~WriteableBuffer) – buffer containing the bytes to read into
out_start (int) – Index to start writing from
out_end (int) – Index to read up to but not include; if None, use
len(out_buffer)
in_start (int) – Index to start writing at
in_end (int) – Index to write up to but not include; if None, use
len(in_buffer)
adafruit_bus_device.spi_device
- SPI Bus Device¶
- class adafruit_bus_device.spi_device.SPIDevice(spi: SPI, chip_select: Optional[DigitalInOut] = None, *, cs_active_value: bool = False, baudrate: int = 100000, polarity: int = 0, phase: int = 0, extra_clocks: int = 0)[source]¶
Represents a single SPI device and manages locking the bus and the device address.
- Parameters
spi (SPI) – The SPI bus the device is on
chip_select (DigitalInOut) – The chip select pin object that implements the DigitalInOut API.
cs_active_value (bool) – Set to true if your device requires CS to be active high. Defaults to false.
baudrate (int) – The SPI baudrate
polarity (int) – The SPI polarity
phase (int) – The SPI phase
extra_clocks (int) – The minimum number of clock cycles to cycle the bus after CS is high. (Used for SD cards.)
Note
This class is NOT built into CircuitPython. See here for install instructions.
Example:
import busio import digitalio from board import * from adafruit_bus_device.spi_device import SPIDevice with busio.SPI(SCK, MOSI, MISO) as spi_bus: cs = digitalio.DigitalInOut(D10) device = SPIDevice(spi_bus, cs) bytes_read = bytearray(4) # The object assigned to spi in the with statements below # is the original spi_bus object. We are using the busio.SPI # operations busio.SPI.readinto() and busio.SPI.write(). with device as spi: spi.readinto(bytes_read) # A second transaction with device as spi: spi.write(bytes_read)