GPIO2_11 is by default high

Hi guys!

I have a strange problem with my beaglebone black board and I couldn’t find a solution. I created/generated some device tree files for some IOs and I observed that for some pins, have a " default" high voltage. I mean that after I load the dtbo, on those pins set as inputs with no pull-up/down and with no input connected, I can read value 1 instead of 0 as normally.

For example, on P8_42 I have this behaviour and this is the device tree:


  • This is a template-generated file from BoneScript


compatible = “ti,beaglebone”, “ti,beaglebone-black”;
part_number = “BS_PINMODE_P8_42_0x2f”;

exclusive-use =

fragment@0 {
target = <&am33xx_pinmux>;
overlay {
bs_pinmode_P8_42_0x2f: pinmux_bs_pinmode_P8_42_0x2f {
pinctrl-single,pins = <0x0b4 0x2f>;

fragment@1 {
target = <&ocp>;
overlay {
bs_pinmode_P8_42_0x2f_pinmux {
compatible = “bone-pinmux-helper”;
status = “okay”;
pinctrl-names = “default”;
pinctrl-0 = <&bs_pinmode_P8_42_0x2f>;

I noticed this behaviour only for P8_43,P8_44,P8_41 and P8_42. For others IOs pins that have similar device tree files ( set up as inputs, with pullup/down disabled, in mode 7->gpio) everything seems perfect.

Can someone tell me why only for those 4 pins I have that behaviour?

I have installed Debian OS with kernel version 3.8.13-bone79 .

Check the SRM. gpio2_8-11 are mapped to LCD_DATA2-5 which map to SYS_BOOT2-5.
The pins are connected to voltage dividers. SYS_BOOT2 is also connected to uSD BOOT button.
If you load these pins during boot, your BBB may not boot correctly.

HDMI and HDMIN are disabled. No uSD card is inserted in BBB at bootup. As a workaround, it should be ok if I configure a pulldown on this pins to maintain a 0, on line… I think… Thanks a lot!

And also the pins are not load during boot…