Hello!

Dominic

Hi everybody, purchased an UP 2/16 last week.
Installed ubuntu 16.04 with up kernel, testing my apps.
So far very pleased with Up's performance and build quality, but struggling with i/o.

DCleri

Hi Domius,

We will release an updated ubilinux (based on Debian Stretch) next week which includes the I/O support.

Later in June also you will be able to download a custom Kernel for Ubuntu which will enable the I/O on UP Squared.

Dominic

Hi Dcleri!
Thank you for prompt reply. Sorry for my ambiguity, my UP is not squared, but 2GB ram / 16GB mmc version.
My problem are floating inputs. This next message from system log is generated when my app sets pull-up / down mode: "gpio27: mode: Failed to open 'drive' for writing: No such file or directory"
Tried with pull-up resistors, no success. Problem gets worse once the UART port is activated.
App is written in Java, using mraa library.
Are internal pull-up/down resistors going to be supported in new release?


BR

Dan O'Donovan

Hi domius
Unfortunately the hardware on UP does not provide configurable pull-up/down resistors for the 40-pin header. So you would need to use external pull-up resistors instead.
-Dan

Dominic

Hi Dan
What is recommended resistor value for the pullup?
Tried many:1.8, 2.2, 4.7, 10k, no success, still floating.

Dan O'Donovan

I'd say it would depend on the rest of the circuit that you have connected. But those resistor values should generally be fine.
Before I could help you further, I think I would need more insight on which pins you're using, how exactly you are setting up and using those pins, and how the issue is manifesting.