The following techniques and safety measures
may be useful for improving independence of function when using the TMS320F28P65x Real-Time
MCU:
- Hold peripherals clocks disabled if the
available peripherals are unused (CLK14 - Peripheral Clock Gating
(PCLKCR)).
- Hold peripherals in reset if the
available peripherals are unused (SYS7 - Peripheral Soft Reset
(SOFTPRES)).
- Power down the analog components cores if
they are not used.
- When possible, separate critical I/O
functions by using non adjacent I/O pins/balls.
- Partition the memory as per the application requirements to respective
processing units and configure the Access Protection Mechanism for Memories, for each memory instance such that
only the permitted masters have access to memory.
- Dual Zone Code Security Module (DCSM) can be used for functional safety as
firewall to protect shared memories, where functions with different safety integrity
levels can be executed from different security zones (zone1, zone2 and unsecured zone)
thus mitigating risk originating due to interference among these.
- ADC11 - Disabling Unused Sources of SOC Inputs to ADC can help avoid
interference from unused peripherals to disturb functionality of ADC.
- DMA9 - Disabling of Unused DMA Trigger Sources can help minimize interference
caused by unintentional DMA transfers.
- CLA11 - Disabling of Unused CLA Task Trigger Sources can mitigate risk of
interference caused by the trigger events.
- When IPC is used in safety critical application, IPC1 - Information Redundancy
Techniques Including End to End Safing can detect failure of interference to CPU
due to unintentional interrupts form IPC module.
- To avoid interference from spurious activity on MCU’s debug port,
JTAG1 - Hardware
Disable of JTAG Port will be helpful in preventing this interference.
- Safety applications running on the CPU can be interfered by
unintentional faulty interrupt events to PIE module. PIE7 - Maintaining Interrupt Handler
for unused interrupts and PIE8 - Online Monitoring of Interrupts
and Events will detect such interfering failures.
- MCU resources in supporting CPU execution such as memory, interrupt
controller, and so forth could be impacted by resources from lower safety integrity safety
function coexisting on same MCU. Safety mechanisms such as CPU9 - External Watchdog, SRAM16 - Information
Redundancy Techniques, SRAM17 - CPU handling of Illegal
Operation, Illegal Results and Instruction Trapping will be able to detect such
interference.
- Critical configuration registers could be victim of interference from
bus masters on MCU which implements lower safety integrity functions. These can be
protected by SYS1 -
Multibit Enable Keys for Control Registers, SYS2 - Lock Mechanism for Control
Registers, SYS8 - EALLOW and MEALLOW Protection for Critical Registers.