We have upgraded the community system as part of the upgrade a password reset is required for all users before login in.

Full Duplex SPI using Software SPI : spi-gpio-custom



  • I have to do a software SPI because the chips I'm using can only communicate full-duplex. For others not so familiar with Linux...LEDE = OpenWRT (https://openwrt.org/packages/start), that caused me some confusion. I used the Onion documentation to point the opkg database to the standard LEDE/OpenWRT database of packages and was able to install kmod-spi-gpio-custom. After a reboot, I am able to insert this module and pass the settings, I found an example in another topic on this forum. I see the device listed in the /dev/ folder, so success!

    Now I'm stuck on how to actually access this...anyone have suggestions? I get permission denied if I just try to access the psuedo file structure, which I'm not surprised about. I'm trying to look at the python-spidev project to get some guidance but...yikes, I'm stuck.

    Anyone have tips?

    The source for the module is here: https://github.com/openwrt/openwrt/blob/master/package/kernel/spi-gpio-custom/src/spi-gpio-custom.c



  • Ok since my device was available in the /dev/ folder as spidev1.0...given I assigned bus0 and deviceid 1 when I ran insmod...I was able to use the standard spidev library in Python to access this newly created spi device. The CS now goes low when I run my python script but I don't see any data or clock signals...I'll check for a conflict with the pins that I assigned to MISO, MOSI and SCK.

    Will report back soon, if this works...then it's actually easy to implement software SPI.


Log in to reply
 

Looks like your connection to Community was lost, please wait while we try to reconnect.