Python GPIO 写入设置 GPIO 电源输出失败

Question

我正在尝试控制单板计算机 (Vocore v2) 运行 Open-Wrt Linux 上的 GPIO 引脚。该脚本试图通过文件系统控制 GPIO 引脚。然而，虽然引脚完美导出，但引脚的值（或功率）从未设置！有谁知道为什么powerPin()从来不设置GPIO管脚的power值？我该如何解决这个问题？

谢谢。

我的 Python 脚本：

 '''
This script is an introductory attempt to create a global Python GPIO control program.


The pinAction class requires several variables to be set:
[pin number]
[direction (read or write)]
[output value (if write is set)]
[read value (if read is set; updates on interval flag)]
[read update interval (if read is set, this is an integer value indicating the frequency of which pin values are read)]
'''

#Import all modules necessary for the script...
from subprocess import call
import sys

class pinAction:
    
    def __init__(self,pin,direction):
        #Set object properties...
        self.pin = int(pin)
        #Test direction argument...
        self.direction = "in" if direction == "in" else "out" if direction == "out" else False
        if not self.direction:
            #Incorrect argument: terminate the program...
            print "Error: pin direction must be 'in' or 'out'. Terminating program..."
            sys.exit()
        else:
            call('echo '+self.direction+' > direction',shell=True)
            
        #Initialize the GPIO pin through the file system...
        call("cd /sys/class/gpio && echo "+str(self.pin)+" > export",shell=True)
        print "Successfully initialized pin "+str(self.pin)+"."
        
    def powerPin(self, power):
        if self.direction == "out":
            print "Setting pin power output..."
            power = 0 if int(power) == 0 else 1 if int(power) == 1 else False
            if not power:
                print "Error: power argument must be an integer or string of '0' or '1'."
            else:
                call("echo "+str(power)+" > value && cat value",shell=True)
                #call("ls && echo "+str(power)+" > value",shell=True)
        else:
            print "Error: pin is not an output pin!"
                        
x = pinAction(1,"out")
#Set pin power to be on...
x.powerPin(1)

脚本在终端中输出以下内容：

Successfully initialized pin 1.

Setting pin power output...

1

Answer 1

问题是每次调用 call() 函数时，您当前的工作目录都会重置为脚本所在的目录。

在您的 powerPin() 函数中，更新行：

call("echo "+str(power)+" > value && cat value",shell=True)

成为

call("cd /sys/class/gpio/gpio{0} && echo {1} > value".format(str(self.pin), str(power)))

以便在目录 /sys/class/gpio/gpio${x} :: 中创建值文件，其中 ${x} 是引脚编号

Python GPIO 写入设置 GPIO 电源输出失败

Python GPIO write to set GPIO power output failing

python

openwrt

vocore