[SOLVED] Cubieboard2 + one wire DS18B20

[Emil]

Hello

Maybe it will help someone. I lost a lot of time trying to connect 1-wire to Cubieboard2 via DVK 522 (it has DS18B20 connection on PB10 /gpio 66/ with external pullup).

I've done steps in http://linux-sunxi.org/1-Wire

 

Quote

 

You don't have to edit the fex-file, but the /boot/armbianEnv.txt and add the lines:

overlays=w1-gpio

param_w1_pin=PB10 # desired pin

param_w1_pin_int_pullup=1 # internal pullup-resistor: 1=on, 0=off

 

 

with different combination and it doesn't work.

In /sys/bus/w1/devices i had only sth like 00-80... 00-40... 00-c00.. without w1_slave file

(i was 100% sure of hardware - it works on waveshare debian image)

 

SOLUTION:

In /boot/armbianEnv.txt lines needs to be without comments:
 

Quote

 

overlays=w1-gpio

param_w1_pin=PB10

param_w1_pin_int_pullup=0

 

 

and that's it

(

overlays are created automatically by config so it will be sth like for example this:

overlays=mmc2 nand uart2 uart3 uart4 uart5 uart6 uart7 w1-gpio

)
 

other interesting behaviour

 

cat /sys/kernel/debug/gpio

gpio-42  (                    |w1                  ) in  hi

I don't know why pin 66 ( https://github.com/cubieplayer/Cubian/wiki/GPIO-Introduction )

has number 42 now

 

I've tried to use PC02

http://linux-sunxi.org/A20/PIO#PC02_.2866.29

and also

"(position of letter in alphabet - 1) * 32 + pin number"

 

 

dmesg output

[   18.227575] sun4i-pinctrl 1c20800.pinctrl: unknown pin PB10             # desired pin
finally helped

 

 

INFO:

Cubieboard2, DVK522

image: Armbian Stretch mainline kernel 4.14.y (legacy kernel doesn't boot) on SATA drive

 

cat /proc/version
Linux version 4.14.84-sunxi (root@armbian.com) (gcc version 7.2.1 20171011 (Linaro GCC 7.2-2017.11)) #3 SMP Sat Dec 1 07:18:41 CET 2018

 

 

[martinayotte]

13 hours ago, Emil said:

I don't know why pin 66

Never use header pin number ... SoC is not aware how manufacturer bring GPIOs to header pins ...