树莓派与Adafruit MAX31856通信失败，报错/dev/spidev0.0不存在

尝试用树莓派读取热电偶温度，已下载所需库、确认连接牢固，但运行代码时持续报错。

运行代码 #

import board 
import digitalio 
import adafruit_max31856 
spi = board.SPI() 
cs = digitalio.DigitalInOut(board.D5) 
cs.direction = digitalio.Direction.OTUPUT 
thermocouple = adafruit_max31856.MAX31856(spi,cs) 
print(thermocouple.temperature) 

报错信息 #

Traceback (most recent call last): 

  File "/home/pi/test4.py", line 6, in <module> 

    spi = board.SPI() 

  File "/usr/local/lib/python3.7/dist-packages/board.py", line 299, in SPI 

    return busio.SPI(SCLK, MOSI, MISO) 

  File "/usr/local/lib/python3.7/dist-packages/busio.py", line 289, in __init__ 

    self._spi = _SPI(portId) 

  File "/usr/local/lib/python3.7/dist-packages/adafruit_blinka/microcontroller/generic_linux/spi.py", line 25, in __init__ 

    self._spi = spi.SPI(device=(portid, 0)) 

  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO/spi.py", line 167, in __init__ 

    raise IOError("{} does not exist".format(device)) 

OSError: /dev/spidev0.0 does not exist

解决方案 #

1. 启用树莓派SPI总线 #

报错核心是/dev/spidev0.0设备不存在，说明SPI总线未启用：

• 打开树莓派配置工具：sudo raspi-config
• 依次选择「Interface Options」→「SPI」，确认选择「Yes」启用SPI
• 重启树莓派：sudo reboot
• 重启后执行ls /dev/spidev*，若看到spidev0.0和spidev0.1，说明SPI已成功启用

2. 修复代码拼写错误 #

代码第6行存在拼写错误：

cs.direction = digitalio.Direction.OTUPUT

需将OTUPUT改为OUTPUT，修正后代码：

cs.direction = digitalio.Direction.OUTPUT

3. 额外检查项 #

• 确认引脚连接：树莓派SCLK（GPIO11）、MOSI（GPIO10）、MISO（GPIO9）需对应连接MAX31856的同名引脚，CS引脚接GPIO5（board.D5）
• 检查用户权限：执行groups查看当前用户是否在spi组中，若不在，执行sudo usermod -aG spi pi添加权限，之后重新登录生效

内容的提问来源于stack exchange，提问作者Nicholas Warren