ESP8266 Community Forum

- Sun Oct 04, 2015 10:58 am #30478 I have tested ADC.when I apply voltages more than 9.6 v it read 1024. so I think voltage reference of it's ADC is 9.6v .Any body did the same?

- Thu Oct 08, 2015 2:25 am #30859

I have tested ADC.when I apply voltages more than 9.6 v it read 1024. so I think voltage reference of it's ADC is 9.6v .Any body did the same?

Woohoo. Thats more than Espressif wrote in their datasheets.
Have a look here: http://bbs.espressif.com/viewtopic.php? ... 1545#p1545

All digital IO pins are protected from over-voltage with a snap-back circuit connected between the
pad and ground. The snap back voltage is typically about 6V, and the holding voltage is 5.8V. This
provides protection from over-voltages and ESD. The output devices are also protected from
reversed voltages with diodes.

found in "0B-ESP8266__Hardware_User_Guide__EN_v1.1.pdf"

Also there a topic about 3.9. ADC (Analog-to-digital Converter)

ESP8266EX is embedded with a 10-bit precision SARADC. Currently, TOUT (Pin6) is defined as ADC
interface..

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

- Thu Oct 15, 2015 3:06 am #31396

I have tested ADC.when I apply voltages more than 9.6 v it read 1024. so I think voltage reference of it's ADC is 9.6v .Any body did the same?

I assume you mean 0.96V, not 9.6V. It can very well the case. It's probably a multiple of some diode's bandgap voltage. It's very hard to make it exactly 1.0V.

- Fri Oct 16, 2015 9:13 pm #31567 I'm pretty sure you don't want to apply 9v to any pin unless you want to fry it.

Did you slowly ramp up the voltage using a high accuracy power source to come to that number? Can you please explain how you arrived at 9.6v.