The C2000 MCU products have a common
architectural definition of operating states. These operating states should be
observed by the system developer in their software and system level design concepts.
The operating states state machine is shown in Figure 4-9. The operating
states can be classified into device boot phase and CPU Subsystem (CPUSS) operation
phase.
The various states of the device
operating states state machine are:
- Powered Off - This is the initial
operating state of TMS320F280015x MCU. No power is applied to either core or I/O
power supply and the device is non-functional. An external supervisor can
perform this action (power-down the TMS320F280015x MCU) in any of the
TMS320F280015x MCU states as response to a system level fault condition or a
fault condition indicated by the TMS320F280015x MCU.
- Reset State – In this state, the
device reset is asserted either using the external pins or using any of the
internal sources.
- Safe State – In the Safe state,
the device is either not performing any functional operations or an internal
fault condition is indicated using the device I/O pins.
- Cold Boot - In the cold boot
state, the CPU remains powered but in reset. When the cold boot process is
completed, the reset of the CPU is internally released, leading to the warm boot
stage.
- Warm Boot - The CPU begins
execution from Boot ROM during the warm boot stage.
- Pre-operational - Transfer of
control from boot code to customer code takes place during this phase.
Application specific configurations (for example, clock frequency, peripheral
enable, pinmux, and so forth) are performed in this phase. Boot time
self-test/proof-test required to ensure proper device operation is performed
during this phase. For details, see ROM8-Power-Up Pre-Operational Security.
- Operational – This marks the
system exiting the pre-operational state and entering the functional state. The
device is capable of supporting safety critical functionality during operational
mode.
The device start-up timeline for both
the CPUs are shown in Figure 4-10.