spidev

3.8 verified Mon Apr 27 auth: no python

Python bindings for Linux SPI access through spidev. Current version 3.8 provides low-level control of SPI devices via the Linux spidev kernel interface. Release cadence is infrequent; maintained on GitHub.

pip install spidev

Common errors

error OSError: [Errno 2] No such file or directory ↓

cause SPI device node does not exist; kernel module not loaded or incorrect bus/device number.

fix

Load the spidev module: 'sudo modprobe spidev' and check /dev for spidev files (e.g., ls /dev/spi*).

error PermissionError: [Errno 13] Permission denied ↓

cause User lacks read/write access to /dev/spidev*.

fix

Run as root or add a udev rule to grant permissions (e.g., 'SUBSYSTEM=="spidev", MODE="0666"').

error AttributeError: module 'spidev' has no attribute 'SpiDev' ↓

cause Incorrect import: using 'import spidev' instead of 'from spidev import SpiDev'.

fix

Use 'from spidev import SpiDev' to import the class.

error TypeError: function takes at most 2 arguments (3 given) ↓

cause Wrong number of arguments when calling 'open_path' — expects a single path string.

fix

Use 'spi.open_path("/dev/spidev0.0")' instead of 'spi.open_path(bus, device)'.

Warnings

gotcha Bits per word default is 8. Changing to other values (e.g., 16) may cause unexpected transfer behavior unless hardware supports it. ↓

fix Set 'spi.bits_per_word = 8' explicitly, or check device datasheet before changing.

breaking In v3.8, the 'open_path' method was added. Older code using only 'open(bus, device)' still works, but dynamic bus allocation may require file path-based opening. ↓

fix Use 'spi.open_path("/dev/spidev0.0")' for dynamic bus numbering, or stick with 'spi.open(bus, device)' for static.

deprecated Using 'spi.xfer2' is deprecated in favor of 'spi.xfer'. xfer2 was a non-standard name and may be removed in future versions. ↓

fix Replace 'spi.xfer2' with 'spi.xfer'.

gotcha Running without root or proper permissions (e.g., no udev rule) yields 'PermissionError' or 'OSError: [Errno 13] Permission denied'. ↓

fix Run as root, or add a udev rule to set permissions on /dev/spidev* (e.g., 'SUBSYSTEM=="spidev", MODE="0666"').

Imports

SpiDev
wrong
```
import spidev
```
correct
```
from spidev import SpiDev
```
Common mistake: 'import spidev' only gives access to the module object, not the SpiDev class. Use 'from spidev import SpiDev' for direct access.

Quickstart

Open SPI bus 0, device 0, transfer bytes, and close.

from spidev import SpiDev

spi = SpiDev()
spi.open(0, 0)  # bus=0, device=0
spi.max_speed_hz = 1000000
spi.mode = 0b00

to_send = [0x01, 0x02, 0x03]
response = spi.xfer(to_send)
print(response)
spi.close()