PINE64

During U-Boot startup I see the following message repeated


This is obviously caused by interrupts from the KEYADC. As far as I can see, this pin is left floating, but should likely be weakly (1..10 MOhm) pulled to GND.

I assume the purpose of this pin is to implement an R2R ladder input, like

http://hackaday.com/2012/03/02/r2r-ladde...e-adc-pin/

(01-30-2016, 08:36 AM)StefanB Wrote: [ -> ]During U-Boot startup I see the following message repeated

Code:

key pressed value=0x1

This is obviously caused by interrupts from the KEYADC. As far as I can see, this pin is left floating, but should likely be weakly (1..10 MOhm) pulled to GND.

I assume the purpose of this pin is to implement an R2R ladder input, like

http://hackaday.com/2012/03/02/r2r-ladde...e-adc-pin/

Good catch, I will inform our Android software engineer to check out.

this is true on the ic ALLWINNER A64 MAIL IC it is the PIN A16 which is an analog input with 6bit resolution
in the documentation : http://files.pine64.org/doc/datasheet/pi...t_V1.1.pdf
look at page 8 and 9