Octavo OSD3358-SM-RED, User Manual

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OSD3358-SM-RED
– User Guide
Rev. 1.0 9/19/2017
Octavo Systems LLC
Copyright 2017
file specified in the boot configuration file uEnv.txt located in /boot/ folder communicates which
peripherals are available and enabled, device drivers that need to be loaded, default pin mux
settings after boot, etc. The device Tree Binary file is a compiled version of a .dts(Device Tree
Source) file. A Device Tree Compiler (dtc) is necessary to convert the source file into the binary
file. The device tree source files for the OSD335x devices and the OSD3358-SM-RED board
are linked below. The best way to write custom device trees is by using the dtb-rebuilder and is
also linked below.
Useful resources:
1. OSD3358-SM-RED device tree files: https://github.com/octavosystems/OSD335x-
Device-Tree
2. Device tree usage: http://elinux.org/Device_Tree_Usage
3. Device tree reference: http://elinux.org/Device_Tree_Reference
4. Device tree rebuilder: https://github.com/RobertCNelson/dtb-rebuilder
5.2.1 Device Tree Overlays
Similar to the capes of Beaglebone Black, capes can be added to the OSD3358-SM-RED
platform for enhanced functionality. The board is cape compatible with existing Bealgebone
Black capes. So, capes for the Beaglebone Black can be used with the OSD3358-SM-RED
board. The additional cape specific setup for Linux is done using Device Tree Overlays.
BeagleBone Black compatible expansion capes also normally include an I2C EEPROM (must
be on I2C2 in the address range of 0x54 to 0x57), that provides information such as the name of
the cape, cape version, part number, and other relevant run-time information. The information
required to load the correct Device Tree Overlay for a specific cape is read from the I2C
EEPROM by the Cape Manager (
http://elinux.org/Capemgr ). See the BeagleBone Black SRM
( https://github.com/beagleboard/beaglebone-black/wiki/System-Reference-Manual
) “Cape
Board Support” section for details. Device Tree Overlays can also be loaded (cape is enabled)
or unloaded (cape is disabled) at run-
time through the cape manager’s /sys interface.
Useful resources:
1. Cape Manager: http://elinux.org/Capemgr
2. Using cape manager and device tree overlays: https://github.com/jadonk/validation-
scripts/tree/master/test-capemgr
3. Beaglebone Black capes: http://elinux.org/Beagleboard:BeagleBone_Capes
4. Device tree overlays tutorial: https://learn.adafruit.com/introduction-to-the-beaglebone-
black-device-tree/exporting-and-unexporting-an-overlay
5.3 Onboard sensor interfacing
As described in section 3 & 4, there are several sensors on OSD3358-SM-RED board. The
board is equipped with a software library and examples to interface with the sensors. The library
package ‘Redperipherallib’ is pre-installed on Linux and allows commands line access to these