16.5.2 Debugger Access Level (DAL)
The PIC32CM Boot ROM supports two levels of debugger access, known as Debugger Access Levels (DALs). These levels define the degree of access a debugger has to the device during and after boot:
- DAL2: Full access. The device is completely open, allowing all operations supported by the device. This level is typically used during development and debugging.
- DAL0: Locked state. The device is highly restricted. Debug access is limited and defined by the user prior to setting DAL to 0.
The active DAL is determined by the value programmed into the ROMCFG DAL fuse. Once set, the DAL governs the debugger's ability to interact with the device, including access to memory, peripherals, and Boot ROM features. Further details on DAL behavior, transitions, and impact on device access are provided below.
Factory Default Value of DAL
The PIC32CM devices are factory programmed with DAL2. Once the device is programmed with DAL0, the DAL level can be raised by issuing CMD_CE_ALL when device Boot ROM is in interactive mode. Alternatively CMD_HOST_DALELEV command could be used to elevate the device DAL if CMD_HOST_DALELEV is not locked.
Device DAL Life Cycle
The Device Life Cycle has primarily two states: Development and Deployed. The Development state provides debug and programming access to the device. Once application development completes, the device can be placed into the Deployed state by programming the Debug Access Level to DAL0. If the Boot ROM commands for CE_ALL and CMD_HOST_DALELEV (see Table 12-2) are not locked, and USERCFG1/1A and ROMCFG fuse memory regions are not write protected, the device can move back to the Development state. If these commands are disabled, and the memory regions locked, then the Development state is unrecoverable from the debug interface.