SPI
Code Example
from periphery import SPI
# Open spidev1.0 with mode 0 and max speed 1MHz
spi = SPI("/dev/spidev1.0", 0, 1000000)
data_out = [0xaa, 0xbb, 0xcc, 0xdd]
data_in = spi.transfer(data_out)
print("shifted out [0x{:02x}, 0x{:02x}, 0x{:02x}, 0x{:02x}]".format(*data_out))
print("shifted in [0x{:02x}, 0x{:02x}, 0x{:02x}, 0x{:02x}]".format(*data_in))
spi.close()
API
- class periphery.SPI(devpath, mode, max_speed, bit_order='msb', bits_per_word=8, extra_flags=0)[source]
Bases:
objectInstantiate a SPI object and open the spidev device at the specified path with the specified SPI mode, max speed in hertz, and the defaults of “msb” bit order and 8 bits per word.
- Parameters:
devpath (str) – spidev device path.
mode (int) – SPI mode, can be 0, 1, 2, 3.
max_speed (int, float) – maximum speed in Hertz.
bit_order (str) – bit order, can be “msb” or “lsb”.
bits_per_word (int) – bits per word.
extra_flags (int) – extra spidev flags to be bitwise-ORed with the SPI mode.
- Returns:
SPI object.
- Return type:
- Raises:
SPIError – if an I/O or OS error occurs.
TypeError – if devpath, mode, max_speed, bit_order, bits_per_word, or extra_flags types are invalid.
ValueError – if mode, bit_order, bits_per_word, or extra_flags values are invalid.
- transfer(data)[source]
Shift out data and return shifted in data.
- Parameters:
data (bytes, bytearray, list) – a byte array or list of 8-bit integers to shift out.
- Returns:
data shifted in.
- Return type:
bytes, bytearray, list
- Raises:
SPIError – if an I/O or OS error occurs.
TypeError – if data type is invalid.
ValueError – if data is not valid bytes.
- property fd
Get the file descriptor of the underlying spidev device.
- Type:
int
- property devpath
Get the device path of the underlying spidev device.
- Type:
str
- property mode
Get or set the SPI mode. Can be 0, 1, 2, 3.
- Raises:
SPIError – if an I/O or OS error occurs.
TypeError – if mode type is not int.
ValueError – if mode value is invalid.
- Type:
int
- property max_speed
Get or set the maximum speed in Hertz.
- Raises:
SPIError – if an I/O or OS error occurs.
TypeError – if max_speed type is not int or float.
- Type:
int, float
- property bit_order
Get or set the SPI bit order. Can be “msb” or “lsb”.
- Raises:
SPIError – if an I/O or OS error occurs.
TypeError – if bit_order type is not str.
ValueError – if bit_order value is invalid.
- Type:
str