3.4 haas506开发教程-example-ads1115
1.ads1115
- 案例说明
使用ads1115模块获取电压值 - main.py
# coding=utf-8
import utime as time
import usys
usys.path.append('/data/pyamp')
import ADS1x15
adc = ADS1x15.ADS1115()
GAIN = 2/3
print('Reading ADS1x15 values, press Ctrl-C to quit...')
while True:
values = [0]*4
for i in range(4):
values[i] = adc.read_adc(i, gain=GAIN)
values[i]=values[i]*0.1875/1000
print('-'*45)
print('| {0:>7} | {1:>7} | {2:>7} | {3:>7} |'.format('IN0','IN1','IN2','IN3'))
print('| {0:>6} | {1:>6} | {2:>6} | {3:>6} |'.format(*values))
print('-'*45)
time.sleep(2)
- ADS1x15.py
# coding=utf-8
import utime as time
'''
# 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
'''
# Register and other configuration values:
ADS1x15_DEFAULT_ADDRESS = 0x48
ADS1x15_POINTER_CONVERSION = 0x00
ADS1x15_POINTER_CONFIG = 0x01
ADS1x15_POINTER_LOW_THRESHOLD = 0x02
ADS1x15_POINTER_HIGH_THRESHOLD = 0x03
ADS1x15_CONFIG_OS_SINGLE = 0x8000
ADS1x15_CONFIG_MUX_OFFSET = 12
# Maping of gain values to config register values.
ADS1x15_CONFIG_GAIN = {
2/3: 0x0000,
1: 0x0200,
2: 0x0400,
4: 0x0600,
8: 0x0800,
16: 0x0A00
}
ADS1x15_CONFIG_MODE_CONTINUOUS = 0x0000
ADS1x15_CONFIG_MODE_SINGLE = 0x0100
# Mapping of data/sample rate to config register values for ADS1015 (faster).
ADS1015_CONFIG_DR = {
128: 0x0000,
250: 0x0020,
490: 0x0040,
920: 0x0060,
1600: 0x0080,
2400: 0x00A0,
3300: 0x00C0
}
# Mapping of data/sample rate to config register values for ADS1115 (slower).
ADS1115_CONFIG_DR = {
8: 0x0000,
16: 0x0020,
32: 0x0040,
64: 0x0060,
128: 0x0080,
250: 0x00A0,
475: 0x00C0,
860: 0x00E0
}
ADS1x15_CONFIG_COMP_WINDOW = 0x0010
ADS1x15_CONFIG_COMP_ACTIVE_HIGH = 0x0008
ADS1x15_CONFIG_COMP_LATCHING = 0x0004
ADS1x15_CONFIG_COMP_QUE = {
1: 0x0000,
2: 0x0001,
4: 0x0002
}
ADS1x15_CONFIG_COMP_QUE_DISABLE = 0x0003
class ADS1x15(object):
def __init__(self,**Kwargs):
#导入I2c
from driver import I2C
#实例化
self._i2c=I2C()
#打开I2c
self._i2c.open("ADS1115")
def _data_rate_default(self):
#子类需要实现 父类的方法，否则报错
raise NotImplementedError("subclass must implemet _data_rate_default!")
def _data_rate_config(self,data_rate):
#子类需要实现 父类的方法，否则报错
raise NotImplementedError("subclass must implemet _data_rate_default!")
def _conversion_value(self, low, high):
#子类需要实现 父类的方法，否则报错
raise NotImplementedError('Subclass must implement _conversion_value function!')
#mux, gain, data_rate, and mode 要在规定的范围内
def _read(self, mux, gain, data_rate, mode):
# Go out of power-down mode for conversion.
config = ADS1x15_CONFIG_OS_SINGLE
# Specify mux value.
config |= (mux & 0x07) << ADS1x15_CONFIG_MUX_OFFSET
#设置增益
if gain not in ADS1x15_CONFIG_GAIN:
raise ValueError('Gain must be one of: 2/3, 1, 2, 4, 8, 16')
config |= ADS1x15_CONFIG_GAIN[gain]
#设置模式(continuous or single shot)
config |= mode
#得到速率，默认128bps
if data_rate is None:
data_rate = self._data_rate_default()
#设置速率
config |= self._data_rate_config(data_rate)
#disable 比较器模式
config |= ADS1x15_CONFIG_COMP_QUE_DISABLE
#I2C的写函数
writeData=bytearray(3)
writeData[0]=ADS1x15_POINTER_CONFIG
writeData[1]=(config >> 8) & 0xFF
writeData[2]=config & 0xFF
self._i2c.write(writeData,3)
#等待ADC采样（根据采样率加上一个很小的偏置，如0.1ms)
time.sleep(1.0/data_rate+0.0001)
#I2C的读函数
readData=bytearray([ADS1x15_POINTER_CONVERSION,0x00])
self._i2c.read(readData,2)
#return 读取到的数据，包含高八位和低八位
return self._conversion_value(readData[1],readData[0])
def read_adc(self, channel, gain=1, data_rate=None):
#读单个ADC通道，通道值取值范围为[0,3]
assert 0 <= channel <= 3, 'Channel must be a value within 0-3!'
# Perform a single shot read and set the mux value to the channel plus
# the highest bit (bit 3) set.
return self._read(channel + 0x04, gain, data_rate, ADS1x15_CONFIG_MODE_SINGLE)
#继承父类
class ADS1115(ADS1x15):
"""ADS1115 16-bit analog to digital converter instance."""
def __init__(self, *args, **kwargs):
super(ADS1115, self).__init__(*args, **kwargs)
def _data_rate_default(self):
#默认速率为128bps
return 128
def _data_rate_config(self, data_rate):
if data_rate not in ADS1115_CONFIG_DR:
raise ValueError('Data rate must be one of: 8, 16, 32, 64, 128, 250, 475, 860')
return ADS1115_CONFIG_DR[data_rate]
def _conversion_value(self, low, high):
#转换16位数据
value = ((high & 0xFF) << 8) | (low & 0xFF)
if value & 0x8000 != 0:
value -= 1 << 16
return value
- board.json
{
"name": "haas506",
"version": "1.0.0",
"io": {
"ADS1115": {
"type": "I2C",
"port": 1,
"addrWidth": 7,
"freq": 400000,
"mode": "master",
"devAddr": 72
},
"serial1":{
"type":"UART",
"port":0,
"dataWidth":8,
"baudRate":115200,
"stopBits":1,
"flowControl":"disable",
"parity":"none"
},
"serial2":{
"type":"UART",
"port":1,
"dataWidth":8,
"baudRate":115200,
"stopBits":1,
"flowControl":"disable",
"parity":"none"
},
"serial3":{
"type":"UART",
"port":2,
"dataWidth":8,
"baudRate":115200,
"stopBits":1,
"flowControl":"disable",
"parity":"none"
}
},
"debugLevel": "ERROR",
"repl":"disable"
}
2.实现步骤
（1）将asd1115模块的VDD、GND、SDA、SCL接入到haas506的I2C接口上，A0、A1、A2、A3接入3.3V以下电源
（2）复制代码到您的文件中
（3）确认端口号
（4）烧录
（5）查看日志
A0、A1接入GND,A2、A3接入3v3
都不接电源的情况下，输出默认值
3.总结
本节介绍了如何使用ADS1115模块来获取电压值。需要注意的有2点：
- 当前gain是2/3,可以测6.144V以内的电压值，可以根据需要更改gain的值
- ads1115模块的所测量的电压值不能超过所接入到ads1115的VDD引脚的电压值
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