如何使用python I2C TCA9548A读取多路复用器

#!/usr/bin/python # Change channel of TCA9548A # Example: sudo ./multiplexer_channel.py 0 import smbus import time import sys I2C_address = 0x77 I2C_bus_number = 1 I2C_ch_0 = 0b00000001 I2C_ch_1 = 0b00000010 I2C_ch_2 = 0b00000100 I2C_ch_3 = 0b00001000 I2C_ch_4 = 0b00010000 I2C_ch_5 = 0b00100000 I2C_ch_6 = 0b01000000 I2C_ch_7 = 0b10000000 def I2C_setup(i2c_channel_setup): bus = smbus.SMBus(I2C_bus_number) bus.write_byte(I2C_address,i2c_channel_setup) time.sleep(0.1) print "TCA9548A I2C channel status:", bin(bus.read_byte(I2C_address)) I2C_setup(int(sys.argv[1]))

from tentacle_pi.BMP180 import BMP180 import time bmp = BMP180(0x70,"/dev/i2c-1") for x in range(0,1005): print "temperature: %s" % bmp.temperature() print "pressure: %s" % bmp.pressure() print "altitude: %s" % bmp.altitude() print time.sleep(2)

# coding=utf-8 import argparse import smbus import time class TCA9548A(object): def __init__(self, bus, address=0x70, ): self.i2c_address = address self.i2c_bus = bus self.bus = smbus.SMBus(self.i2c_bus) def setup(self, channel): try: self.bus.write_byte(self.i2c_address, channel) return 1, "Success" except Exception as msg: return 0, "Fail: {}".format(msg) def read(self): time.sleep(0.1) return self.bus.read_byte(self.i2c_address) def menu(): parser = argparse.ArgumentParser(description='Select I2C address and channel of TCA9548A I2C multiplexer') parser.add_argument('-a', '--address', metavar='ADDRESS', type=int, help='I2C address of the multiplexer, only last two digits, (ex. enter "70" if 0x70)', required=True) parser.add_argument('-b', '--bus', metavar='BUS', type=int, help='I2C bus of the multiplexer', required=True) group = parser.add_mutually_exclusive_group() group.add_argument('-c', '--channel', metavar='CHANNEL', type=int, help='Channel to be activated with the multiplexer') group.add_argument('-r', '--read', action='store_true', help='Only read multiplexer and return channel number') args = parser.parse_args() i2c_address = int(str(args.address), 16) multiplexer = TCA9548A(args.bus, i2c_address) if args.channel: multiplexer.setup(args.channel) read_response = multiplexer.read() print("TCA9548A I2C channel status: {} (channel {})".format(bin(read_response), read_response)) if __name__ == "__main__": menu()

pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 0 TCA9548A I2C channel status: 0b11111000 (channel 248) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.599998474 pressure: 40287 altitude: -31.4230690002 temperature: -52.5 pressure: 40183 altitude: -31.5887317657 temperature: -52.5 pressure: 40281 altitude: -37.2313270569 temperature: -52.5 pressure: 40284 altitude: -34.078414917 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 1 TCA9548A I2C channel status: 0b1 (channel 1) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 40166 altitude: -31.7548980713 temperature: -52.4000015259 pressure: 40163 altitude: -34.5762786865 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 2 TCA9548A I2C channel status: 0b0 (channel 0) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 28375 altitude: 1204.44226074 temperature: -52.4000015259 pressure: 28303 altitude: 1222.52453613 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 3 TCA9548A I2C channel status: 0b0 (channel 0) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 28304 altitude: 1205.19128418 temperature: -52.5 pressure: 28301 altitude: 1222.90002441 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 4 TCA9548A I2C channel status: 0b100 (channel 4) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 40136 altitude: -46.9332351685 temperature: -52.5 pressure: 40116 altitude: -47.5958938599 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 5 TCA9548A I2C channel status: 0b101 (channel 5) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 40185 altitude: -46.9332351685 temperature: -52.5 pressure: 40136 altitude: -47.0986480713 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 6 TCA9548A I2C channel status: 0b0 (channel 0) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 28365 altitude: 1216.15002441 temperature: -52.5 pressure: 28297 altitude: 1215.96289062 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index3.py -a 77 -b 1 -c 7 TCA9548A I2C channel status: 0b0 (channel 0) pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.p python: can't open file 'index2.p': [Errno 2] No such file or directory pi@pi1:~/Documents/NodeJSProjects/PythonTests $ sudo python index2.py temperature: -125.699996948 pressure: 28368 altitude: 1219.89953613 temperature: -52.5 pressure: 28283 altitude: 1219.71179199 temperature: -52.5 pressure: 28353 altitude: 1219.71179199 ^CTraceback (most recent call last): File "index2.py", line 11, in <module> time.sleep(2) KeyboardInterrupt pi@pi1:~/Documents/NodeJSProjects/PythonTests $ ^C

1条回答

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1楼 · 发布于 2024-10-01 22:42:55

我修改了您原来的示例，这对我来说很有用：

我的TCA9548A.py如下所示：

#!/usr/bin/python
# intended for import to change channel of TCA9548A
# import then call I2C_setup(multiplexer_addr,multiplexer_channel)

import smbus
import time
import sys

channel_array=[0b00000001,0b00000010,0b00000100,0b00001000,0b00010000,0b00100000,0b01000000,0b10000000]

def I2C_setup(multiplexer,i2c_channel_setup):
    bus = smbus.SMBus(1)
    bus.write_byte(multiplexer,channel_array[i2c_channel_setup])
    time.sleep(0.01)
    #uncomment to debug #print("TCA9548A I2C channel status:", bin(bus.read_byte(multiplexer)))

然后在同一目录中，我有一个文件read_sensor.py，它利用了您的示例：

#!/usr/bin/python

import TCA9548A

# set specific multiplexer to a specific channel
# TCA9548A.I2C_setup( multiplexer_addr , multiplexer_channel )
TCA9548A.I2C_setup(0x70,5)

接下来，根据需要导入库并从传感器获取数据。我有多个BMP280，它们都具有相同的0x76地址。因此，当我在0x76从BMP280传感器读取数据时，多路复用器将只选择一个通道，并向I2C线路开放。下一步，我可能会转到TCA9548A.I2C_设置（0x70,6），然后在0x76再次从BMP280读取数据，但我将从该多路复用器通道6上的下一个BMP280接收数据

我有另一个多路复用器，我将通过它的自定义地址0x71调用它。我把它的A0引脚高拉到VCC，将多路复用器的地址更改为0x71。请注意，我这里的代码没有利用多路复用器不选择通道的能力，因此请注意，任何多路复用器的最后选择通道都将对I2C线路开放。我没有像在Adafruit's example中那样使用Wire.write（0）方法。。。因此，在使用多个多路复用器上的通道之前，可能需要在未使用的多路复用器上选择未使用的通道，或者使用GPIO将多路复用器RST引脚拉低以禁用它

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