8.1.2 Modes of Operation

Access control is based on the device mode of operation. There are three device modes of operation related to security:

• Mission mode
• Debug mode
• ICSP programming mode

Mission Mode is the default device mode of operation. After Reset, code in the user program Flash is executed. After booting, Mission mode also supports code execution from RAM. Execution from RAM is not visible to the security module and does not compromise security module functions.

Debug Mode can be entered either at Reset or upon hitting a debug breakpoint. It executes debug executive code stored in a dedicated Flash space separate from user program Flash to support in-circuit debugging.

ICSP Programming Mode provides the device access using the external ICSP programming tools.