ADC attenuation

[AlbertHoevenaars]

I am trying to use the ADC input on an ESP32-WROOM-32 with the following code (using PyCharm & Micropython):

`from machine import ADC, Pin

adc1 = ADC(Pin(32))
val = adc1.read_u16()

adc1.atten(ADC.ATTN_11DB)
`

I am getting an error message on the word atten "Unresolved attribute reference on 'atten' for class 'ADC'. Tried a lot of other solutions from all kind of websites, but nothing helps.

Someone having an idea how to solve this

Thanks in advance

[GitHubsSilverBullet]

Connect with a terminal and then:
Try a print(dir(ADC)) to show what's available.

[AlbertHoevenaars]

After giving the print command I get:
['class', 'name', 'read', 'ATTN_0DB', 'ATTN_11DB', 'ATTN_2_5DB', 'ATTN_6DB', 'WIDTH_10BIT', 'WIDTH_11BIT', 'WIDTH_12BIT', 'WIDTH_9BIT', 'bases', 'dict', 'atten', 'block', 'init', 'read_u16', 'read_uv', 'width']

So ATTn_11DB is there

[GitHubsSilverBullet]

That's about three lines of code. Wouldn't it be possible to open a simple terminal and just type'em in?
(Asks the guy using vi and has never had a problem since) ;-)

[robert-hh]

At the REPL prompt I can issue these few lines of code without any error. So better skip the IDE. Which one did you use?

[AlbertHoevenaars]

I use PyCharm 2024.2.6 (Cummunity Edition)
When I look in the file machine.pyi in directory C:\Users<username>\AppData\Roaming\JetBrains\PyCharmCE2024.2\plugins\intellij-micropython\typehints\micropython, then there is no attenuation settings. This is the class that I find:
`
class ADC:
"""
The ADC class provides an interface to analog-to-digital convertors, and
represents a single endpoint that can sample a continuous voltage and
convert it to a discretised value.

Example usage::

  import machine

  adc = machine.ADC(pin)   # create an ADC object acting on a pin
  val = adc.read_u16()     # read a raw analog value in the range 0-65535

"""

def __init__(self, pin: int | Pin, /):
    """
  Access the ADC associated with a source identified by *id*.  This
  *id* may be an integer (usually specifying a channel number), a
  :ref:`Pin <machine.Pin>` object, or other value supported by the
  underlying machine.
  """
def read_u16(self) -> int:
    """
  Take an analog reading and return an integer in the range 0-65535.
  The return value represents the raw reading taken by the ADC, scaled
  such that the minimum value is 0 and the maximum value is 65535.
  """

`

[scruss]

I use PyCharm 2024.2.6 (Community Edition)

I think that's the problem. Two other people have reported that your code works in this thread.

Using a SparkFun ThingPlus-ESP32 flashed with MicroPython v1.26.0, connected via mpremote, this code:

from machine import ADC, Pin

adc1 = ADC(Pin(32))
val = adc1.read_u16()
print("Before atten:", val)
adc1.atten(ADC.ATTN_11DB)
val = adc1.read_u16()
print("After  atten:", val)

outputs:

Before atten: 10962
After  atten: 9506

with no errors. Whatever PyCharm is telling you is wrong.

[Josverl]

The stub files included with the (old) micropython plugin that you are using were handcrafted for a pyboard, and for which maintenance seems to have stopped.
When using pycharm + Micropython my recommendation would be to switch to a newer plugin : MicroPython Tools
That bundles the MicroPyhon stubs, which include the ADC.atten() method since v1.12 , although with limited parameter info)

( but note the methods is marked as Legacy aka deprecated in MicroPython's docs)

[AlbertHoevenaars]

I would like to thank everyone for the given comments and help. Found out that although PyCharm was given a warning the ATTEN commands works in the ESP32 that I use together with micropython. I also will have a look in the newer MicroPython Tools (thanks Josverl)

Best Regards