PRU Replicap.dts explanation


I have successfully configure the PRU and test it (PRU0 and PRU1).
To do so I have used the following DTS :
And the example there :

However, I was thinking that there were may be two many functionality in this DTS that I didn’t want to.
So I decided, to delete all the elements which didn’t disable the PRU.
Finally I arrived with this attached DTS : BB-BONE-CST-CAP-00A0.dts

However I didn’t understand why I should configured DIR_(E,H,X,Y,Z), STEP_(E,H,X,Y,Z), FAULT (E,H,X,Y,Z) ?
And Why should I configured them as GPIO.

In the meantime for example here I didn’t understand the zero after the GPIO number :

stepper_x{ pin-names = "Replic:pru-step_x", "Replic:pru-dir_x"; gpios = <&gpio0 27 0 &gpio1 29 0>; };

In addition for

fault_x { label = "Replic:Fault-X"; debounce_interval = <50>; linux,code = <90>; gpios = <&gpio2 4 0x5>; gpio-key,wakeup; };

I didn’t understand the debounce_interval and the 0x5 value.

So if someone has some explanation about it, or if you have some remark on what I should/shouldn’t delete, I will be pleased to hear about.

Remark :

but they didn’t allowed me to make the PRU work.

#uname -a Linux beagle01 4.1.21-bone-rt-r20 #1 Wed Apr 6 19:53:34 UTC 2016 armv7l GNU/Linux

BB-BONE-CST-CAP-00A0.dts (7.23 KB)