Building and running the example

Finally, we are putting all we have learned about TrustZone-M into practice, by activating the option flags needed to enable TrustZone-M and running the two software components associated with the execution domains.

Enabling TrustZone-M

By default, TrustZone-M is turned off on our microcontroller when it is in its factory state. Turning on TrustZone is a one-way operation, but it is typically not irreversible unless combined with other hardware-assisted protection mechanisms that make it impossible to disable it when the embedded system is deployed. Disabling TrustZone once enabled, however, requires a more complex procedure than just clearing one bit in a register.

Important note

Please refer to your microcontroller’s reference manual and application notes, and ensure that you understand the procedure and the consequences of enabling or attempting to disable TrustZone-M on your device.

On the reference platform, to enable TrustZone...