ESP8266 Community Forum

- Thu Jun 11, 2015 8:35 pm #20212 I can prettywell assure you that the Arduino IDE is not the likely cause. They have been doing analogue reads for 5 years plus . The library might be the culprit but again I doubt it .

There is something peculiar about the analog pin on these modules . people swear blind they cannot read better than 1 Volt input and I have 1 running (ESP 12)and it seems to be reading up to 2.85 Volts but I could be mistaken ,I am working on checking that now.

The change though from NodeMCU to Arduino as an upload facility for the machine code might be assuming certain settings or pin connections that you are not aware of . ie Up to IDE 1.6.3 the pins were not addressed as they are now following the board names although I think the analog pin has stayed the same .

Perhaps you can see what I mean though . It might be some more subtle difference.

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Thu Jun 11, 2015 9:42 pm #20216

There is something peculiar about the analog pin on these modules . people swear blind they cannot read better than 1 Volt input and I have 1 running (ESP 12)and it seems to be reading up to 2.85 Volts but I could be mistaken ,I am working on checking that now.

While there's a lot of information missing in the datasheet, it clearly states:

The input voltage range is 0 to 1.0 V when TOUT is connected to external
circuit.

See section 3.8: http://bbs.espressif.com/download/file.php?id=439
If you have applied higher voltages to the TOUT pin, you may have damaged the ADC (proper maximum ratings & electrical characteristics are among the missing information, so it's unclear at which voltage the ADC will be damaged).

- Thu Jun 11, 2015 10:12 pm #20217 Mate! You have missed the point.
You refer to the early modules .
The later ones may be different I think
Thats not the data sheet on the ESP12's
Their Analog pin is ADC not TOUT

Get you modules here:

https://www.banggood.com/custlink/KvGGhGF4wG

- Thu Jun 11, 2015 11:39 pm #20223 If you have a look at the PCB layout images postet on pretty much every vendor site, you will notice that the pad labeled "ADC" is connected directly to the ESPs pin 6 (TOUT).

However this is starting to go off topic, let's try to return to the original issue:
@Tawhiz20: the datasheet suggests, that to use the external ADC a specific byte in the config section of the flash must be set to configure the supply voltage. If that byte is 0xFF (which would be the case if the sector was erased), the ADC wil be configured to measure VCC.
I suggest you try to get the default config file mentioned in the datasheet (should be included in the official SDK), change the byte as described in the datasheet and flash it to your ESP (instructions on where and how to flash it should be included in the SDK as well).