Non-native OAD¶
Since TI-OpenThread uses the BIM infrastructure for updating firmware images, an OAD-enabled TI-OpenThread firmware image can essentially be transported over any other TI wireless stack that supports OAD, as long as the Target device is OAD-enabled.
BLE OAD¶
Warning
The BLE-Stack OAD Profile does not implement or perform any security or authentication mechanisms as part of the firmware update process. System developers should take measures to adequately authenticate peer devices and only accept and/or apply firmware images transferred from trusted sources via the OAD Profile. TI recommends applications use Bluetooth LE Secure Connections (LESC) with Man-in-the-Middle (MITM) protection with peer devices when performing wireless firmware updates, although the use of the LESC feature does not itself guarantee image authenticity.
For example, the BLE Stack can be used as its transport. The TI-OpenThread firmware image will use the BLE OAD process as a black-box for the purposes of this example. The specifics of downloading the TI-OpenThread firmware image into external flash are not covered here.
Note
Consult the BLE User’s Guide for more details on the BLE OAD process.
For the OAD Distributor, a CC13x2 or CC26x2 running Host Test will be used, which is connected to BTool. This configuration is responsible for taking the TI-OpenThread firmware image and sending it to a BLE device with the OAD profile.
For the OAD Target, a CC13x2 or CC26x2 running a BLE example application with the OAD profile (simple_peripheral, project_zero) will be used. This device will allow BTool + Host Test to download a new image to the CC13x2 or CC26x2. This example image will also be marked as the factory image, allowing multiple image updates by reverting to the factory image.
The running TI-OpenThread firmware image can be invalidated by pressing the Left button (BTN-1) on the CC13x2 or CC26x2. Once the running TI-OpenThread firmware image is invalidated, the BIM will load the factory image from external flash. This factory image is the original example image programmed on the CC13x2 or CC26x2, in this fashion a new image may be downloaded onto the CC13x2 or CC26x2.
See Figure OAD Application state diagram how the interaction between a TI-OpenThread application, some other OAD-enabled application and BIM works.
![@startuml
scale 0.8
[*] --> BIM
state BIM {
[*] --> checkImage
checkImage : Check if the\ncurrent image\nis invalid
checkImage --> loadFactory : Image invalid
checkImage --> runImage : Image valid
loadFactory : Copy image\nfrom sector 0
loadFactory --> otherApp : System\nreset
runImage : Jump to\nloaded image
runImage --> threadApp : System\nreset
runImage --> otherApp : System\nreset
}
state otherApp {
[*] --> writeFactory
writeFactory : Write the\nfactory image\nto external flash
writeFactory --> idle
idle : Wait for\nconnection
idle --> idle
idle --> downloadImage
downloadImage : New image\ndownloaded into\nexternal flash
downloadImage --> threadApp : System\nreset
}
state threadApp {
[*] --> startup
startup : Check if\nbutton pressed
startup --> invalidate : Button is\npressed
startup --> normalOperation : Button is\nnot pressed
invalidate : Invalidate CRC\nfor running image
invalidate --> BIM : System\nreset
normalOperation : Thread example runs\nas normal until reset
normalOperation --> normalOperation
normalOperation --> BIM : System\nreset
}
@enduml](../_images/plantuml-2eba37bb8b437dfc00c8a344462f957df0632262.png)
Figure 56. OAD Application state diagram¶