使用 i2c 从 Raspberry Pi 读取 ADS1115 时出现问题

Question

我正在尝试使用 adc 转换器 (ads1115 )。

但是当我尝试运行示例脚本时；简单测试.py

我得到：

读取 ADS1x15 值，按 Ctrl-C 退出...

| 0 | 1 | 2 | 3 |

回溯（最近一次调用最后）：文件“simpletest.py”，第 43 行，值 [i] = adc.read_adc(i, Gain=GAIN) 文件“build/bdist.linux-armv7l/egg/Adafruit_ADS1x15/ADS1x15. py”，第 192 行，在 read_adc 文件“build/bdist.linux-armv7l/egg/Adafruit_ADS1x15/ADS1x15.py”中，第 133 行，在 _read 文件“build/bdist.linux-armv7l/egg/Adafruit_GPIO/I2C.py”中，第 136 行，readList 文件“build/bdist.linux-armv7l/egg/Adafruit_PureIO/smbus.py”，第 216 行，read_i2c_block_data 类型错误：需要一个字符串

当我运行诊断命令：i2cdetect 时，我得到了这个

i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --        

显示错误消息的 python 脚本（simpletest.py）的完整代码：

# Simple demo of reading each analog input from the ADS1x15 and printing it to
# the screen.
# Author: Tony DiCola
# License: Public Domain
import time

# Import the ADS1x15 module.
import Adafruit_ADS1x15


# Create an ADS1115 ADC (16-bit) instance.
adc = Adafruit_ADS1x15.ADS1115()

# Or create an ADS1015 ADC (12-bit) instance.
#adc = Adafruit_ADS1x15.ADS1015()

# Note you can change the I2C address from its default (0x48), and/or the I2C
# bus by passing in these optional parameters:
#adc = Adafruit_ADS1x15.ADS1015(address=0x49, busnum=1)

# Choose a gain of 1 for reading voltages from 0 to 4.09V.
# Or pick a different gain to change the range of voltages that are read:
#  - 2/3 = +/-6.144V
#  -   1 = +/-4.096V
#  -   2 = +/-2.048V
#  -   4 = +/-1.024V
#  -   8 = +/-0.512V
#  -  16 = +/-0.256V
# See table 3 in the ADS1015/ADS1115 datasheet for more info on gain.
GAIN = 1

print('Reading ADS1x15 values, press Ctrl-C to quit...')
# Print nice channel column headers.
print('| {0:>6} | {1:>6} | {2:>6} | {3:>6} |'.format(*range(4)))
print('-' * 37)
# Main loop.
while True:
    # Read all the ADC channel values in a list.
    values = [0]*4
    for i in range(4):
        # Read the specified ADC channel using the previously set gain value.
        values[i] = adc.read_adc(i, gain=GAIN)
        # Note you can also pass in an optional data_rate parameter that controls
        # the ADC conversion time (in samples/second). Each chip has a different
        # set of allowed data rate values, see datasheet Table 9 config register
        # DR bit values.
        #values[i] = adc.read_adc(i, gain=GAIN, data_rate=128)
        # Each value will be a 12 or 16 bit signed integer value depending on the
        # ADC (ADS1015 = 12-bit, ADS1115 = 16-bit).
    # Print the ADC values.
    print('| {0:>6`enter code here`} | {1:>6} | {2:>6} | {3:>6} |'.format(*values))
    # Pause for half a second.
    time.sleep(0.5) 

请指教。

凯文

Answer 1

我想补充一点，不恰当的接线可能会导致 I2C 地址在操作过程中发生变化，从而导致设备无法在原始地址上进行访问。

我编写了一个示例程序来尝试 ADS1115 的几种配置，而不使用 AdaFruit 库，这似乎对一些人有所帮助： http ://smartypies.com/projects/ads1115-with-raspberrypi-and-python/ads1115runner