Lincoln Privilege Mode Example

From Manuals

Compatibility Lincoln 60, Lincoln 60E

This example application demonstrates the how to change between privilege and unprivilege mode. The Cortex-M3 supports two operating modes, Thread and Handler with two levels of access for the code, privileged and unprivileged, enabling the implementation of complex and open systems without sacrificing the security of the application. Unprivileged code execution limits or excludes access to some resources like certain instructions and specific memory locations. The Thread mode is the typical operating mode and supports both privileged and unprivileged code. The Handler mode is entered when an exception occurs and all code is privileged during this mode.

The first UART, which is connected to the COM1 on the Lincoln microcontroller board, is configured for 115,200 bits per second, and 8-n-1 mode. When the program is started a message will be printed to the terminal. A read is attmpted by pressing the 1 key on the keyboard. After it is succesful a read is attempted to region 6 by pressing the 2 key on the keyboard. The read is unsuccessful because the region is protected by the MPU.