I was hoping to get some guidance on how to integrate the necessary elements for the interrupts and GPIO. I have not had any luck with using the examples I have found from Libre.
This is the last item needed to complete a port of the SW from RaspberryPi to Libre and I have been stuck for quite a few weeks trying to get something going. Any help from the community would be greatly appreciated.
@angus@librecomputer@GeertVc@Iain_R any help with this would be much appreciated. I have seen from the forum that you have gotten the MCP23017 to talk with the LePotato successfully
Raspberry Pi overlays are non-generic. They put a lot of hacks (brcm) that is specific to Raspberry Pi Broadcom SoC. Simply copying it verbatim is not going to work. An overlay usually requires the following:
Compatible string from a driver in the Linux kernel
GPIO pins used so that they can be locked away from other software access
GPIO pins that act as interrupts and their interrupt parents
For I2C and SPI devices, the address or channel select
Status field
We don’t have any devices to test and create the overlay.
Hey @angus and @librecomputer I got this to work finally but it required adding a 1k pull up resistor to pins 3 and 5. @librecomputer you mentioned that this was fixed in the most recent build but I am on the latest image from Libre and have ran an apt-get install and update.
How do I get those pull ups to be active without external resistors?
You can flash the latest bootloader to your image using libretech-flash-tool. It sets the internal pull ups. However on some designs, it may not be enough.