The TMS320F280013x MCU product architecture
provides different levels of fault indication from internal safety mechanisms using
CPU interrupt, non maskable interrupt (NMI), assertion of ERRORSTS pin, assertion of
CPU input reset, and assertion of warm reset (XRSn). The fault response is the
action that is taken by the TMS320F280013x MCU or system when a fault is indicated.
Multiple potential fault responses are possible during a fault indication. The
system integrator is responsible to determine which fault response must be taken to
verify consistency with the system safety concept. The fault indication ordered in
terms of severity (device power down being the most severe) is shown in Figure 6-1.
- Device powerdown: This is the highest priority
fault response where the external component (see Section 4.4.1) detects malfunctioning of the device, or other system components, and powers
down the TMS320F280013x MCU. From this state, re-entering cold boot to attempt
recovery is possible.
- Assertion of XRSn: The XRSn reset can be
generated from an internal or external monitor that detects a critical fault
having the potential to violate a safety goal. Internal sources generate this
fault response when the TMS320F280013x MCU is not able to handle the internal
fault condition by itself (for example, CPU1,or controller CPU, is not able to
handle NMI by itself). From this state, re-entering cold boot to attempt
recovery is possible.
- Assertion of CPU reset: CPU reset changes the
state of the CPU from a pre-operational, or operational, state to warm-boot
phase. The CPU reset is generated from an internal monitor that detects any
security violations. Security violations can be the effect of a fault
condition.
- Non maskable interrupt (NMI) and assertion of
ERRORSTS pin: C28x CPU supports a non maskable interrupt (NMI), which has a
higher priority than all other interrupts. The TMS320F280013x MCU is equipped
with a NMIWD module responsible for generating NMI to the C28x CPU. ERRORSTS pin
is also asserted with NMI. Depending on the system level requirements, the fault
can be handled either internal to the TMS320F280013x MCU using software or at
the system level using the ERRORSTS pin information.
- CPU interrupt: CPU interrupt allows events
external to the CPU to generate a program-sequence, context transfer to an
interrupt handler where software has an opportunity to manage the fault. The
peripheral interrupt expansion (PIE) block multiplexes multiple interrupt
sources into a smaller set of CPU interrupt inputs.