ESP8266 Community Forum

gerardwr wrote:Had no clue what a MCP23017 is, it's a I2C IO-expander with 16 GPIO pins.

I read somewhere about I2C IO-expanders with some digital AND analog IO's. Have some experience with them? Could be a solution for all the people that cry over not having a connection to the ADC TOUT pin on their ESP board.

Try this:
http://www.analog.com/en/analog-to-digi ... oduct.html

8 pins that can be configured either as 12bit ADC, 12bit DAC, digital input or digital output. Internal reference, 0.2%
Should work even with the ESP-01.

uhrheber wrote:Try this:
http://www.analog.com/en/analog-to-digi ... oduct.html

8 pins that can be configured either as 12bit ADC, 12bit DAC, digital input or digital output. Internal reference, 0.2%
Should work even with the ESP-01.

Nice, especially the fact that EVERY pin can be either DIGITAL or ANALOG.

Price ($3.82 from 100pcs) is not too bad, around the price of an ESP8266

If lower 8 bits resolution is acceptable, there is a even cheaper I2C ADC, the PCF8591 from NXP.
Also ElectroDragon has a small board for $2.40 that use hits chip : http://www.electrodragon.com/product/pcf8591-adc-dac-adda-analog-digital-converter-module/