10 Monitoring and Diagnostic Mechanisms

Below is the list given for the main monitoring and diagnostic mechanisms available in the Functional Safety-Compliant IWR2243 device.

MSS R4F is the processor used for running TI's Functional Firmware stored in the ROM that helps in the execution of the API calls issued by the host processor. (It is not a customer programmable core)

Table 10-1 Monitoring and Diagnostic Mechanisms for IWR2243

S No	Feature	Description
1	Boot time LBIST For MSS R4F Core and associated VIM	IWR2243 architecture supports hardware logic BIST (LBIST) engine self-test Controller (STC). This logic is used to provide a very high diagnostic coverage (>90%) on the MSS R4F CPU core and Vectored Interrupt Module (VIM) at a transistor level. LBIST for the CPU and VIM are triggered by the bootloader.
2	Boot time PBIST for MSS R4F TCM Memories	MSS R4F has three Tightly coupled Memories (TCM) memories TCMA, TCMB0 and TCMB1. IWR2243 architecture supports a hardware programmable memory BIST (PBIST) engine. This logic is used to provide a very high diagnostic coverage (March-13n) on the implemented MSS R4F TCMs at a transistor level. PBIST for TCM memories is triggered by Bootloader at the boot time . CPU stays there in while loop and does not proceed further if a fault is identified.
3	End to End ECC for MSS R4F TCM Memories	TCMs diagnostic is supported by Single error correction double error detection (SECDED) ECC diagnostic. An 8-bit code word is used to store the ECC data as calculated over the 64-bit data bus. ECC evaluation is done by the ECC control logic inside the CPU. This scheme provides end-to-end diagnostics on the transmissions between CPU and TCM. CPU is configured to have predetermined response (Ignore or Abort generation) to single and double bit error conditions.
4	MSS R4F TCM bit multiplexing	Logical TCM word and its associated ECC code is split and stored in two physical SRAM banks. This scheme provides an inherent diagnostic mechanism for address decode failures in the physical SRAM banks. Faults in the bank addressing are detected by the CPU as an ECC fault.Further, bit multiplexing scheme implemented such that the bits accessed to generate a logical (CPU) word are not physically adjacent. This scheme helps to reduce the probability of physical multi-bit faults resulting in logical multi-bit faults; rather they manifest as multiple single bit faults. As the SECDED TCM ECC can correct a single bit fault in a logical word, this scheme improves the usefulness of the TCM ECC diagnostic.
5	Clock Monitor	IWR2243 architecture supports Three Digital Clock Comparators (DCCs) and an internal RCOSC. Dual functionality is provided by these modules – Clock detection and Clock Monitoring. DCCint is used to check the availability/range of Reference clock at boot otherwise the device is moved into limp mode (Device still boots but on 10MHz RCOSC clock source. This provides debug capability). DCCint is only used by boot loader during boot time. It is disabled once the APLL is enabled and locked. DCC1 is dedicated for APLL lock detection monitoring, comparing the APLL output divided version with the Reference input clock of the device. Initially (before configuring APLL), DCC1 is used by bootloader to identify the precise frequency of reference input clock against the internal RCOSC clock source. Failure detection for DCC1 would cause the device to go into limp mode. Clock Compare module (CCC) module is used to compare the APLL divided down frequency with reference clock (XTAL). Failure detection is indicated by the nERROR OUT signal.
6	RTI/WD for MSS R4F	Internal watchdog is enabled by the bootloader in a windowed watchdog (DWWD) mode.. Watchdog expiry issues an internal warm reset and nERROR OUT signal to the host.
7	MPU for MSS R4F	Cortex-R4F CPU includes an MPU. The MPU logic can be used to provide spatial separation of software tasks in the device memory. Cortex-R4F MPU supports 12 regions. It is expected that the operating system controls the MPU and changes the MPU settings based on the needs of each task. A violation of a configured memory protection policy results in a CPU abort.
8	PBIST for Peripheral interface SRAMs - SPI, I2C	IWR2243 architecture supports a hardware programmable memory BIST (PBIST) engine for Peripheral SRAMs as well. PBIST for peripheral SRAM memories is triggered by the bootloader. The PBIST tests are destructive to memory contents, and as such are typically run only at boot time. . Any fault detected by the PBIST results in an error indicated in PBIST and boot status response message.
9	ECC for Peripheral interface SRAMs – SPI, I2C	Peripheral interface SRAMs diagnostic is supported by Single error correction double error detection (SECDED) ECC diagnostic. When a single or double bit error is detected the error is indicated by nERROR (double bit error) or via SPI message (single bit error).
10	Cyclic Redundancy Check –Main SS	Cyclic Redundancy Check (CRC) module is available for the Main SS. The firmware uses this feature for data transfer checks in mailbox and SPI communication.
11	MPU for DMAs	IWR2243 architecture supports MPUs on Main SS DMAs. The firmware uses this for stack protection.
12	Boot time LBIST For BIST R4F Core and associated VIM	IWR2243 architecture supports hardware logic BIST (LBIST) even for BIST R4F core and associated VIM module. This logic provides very high diagnostic coverage (>90%) on the BIST R4F CPU core and VIM. This is triggered by MSS R4F boot loader at boot time and it does not proceed further if the fault is detected.
13	Boot time PBIST for BIST R4F TCM Memories	IWR2243 architecture supports a hardware programmable memory BIST (PBIST) engine for BIST R4F TCMs which provide a very high diagnostic coverage (March-13n) on the BIST R4F TCMs. PBIST is triggered at the power up of the BIST R4F.
14	End to End ECC for BIST R4F TCM Memories	BIST R4F TCMs diagnostic is supported by Single error correction double error detection (SECDED) ECC diagnostic. Single bit error is communicated to the BIST R4FCPU while double bit error is communicated to MSS R4F as an interrupt which sends a async event to the host.
15	BIST R4F TCM bit multiplexing	Logical TCM word and its associated ECC code is split and stored in two physical SRAM banks. This scheme provides an inherent diagnostic mechanism for address decode failures in the physical SRAM banks and helps to reduce the probability of physical multi-bit faults resulting in logical multi-bit faults.
16	Temperature Sensors	IWR2243 architecture supports various temperature sensors all across the device (next to power hungry modules such as PAs, DSP etc) which is monitored during the inter-frame period.⁽¹⁾
17	Tx Power Monitors	IWR2243 architecture supports power detectors at the Tx output.⁽²⁾
18	Error Signaling Error Output	When a diagnostic detects a fault, the error must be indicated. The IWR2243 architecture provides aggregation of fault indication from internal monitoring/diagnostic mechanisms using nERROR signaling or async event over SPI interface.
19	Synthesizer (Chirp) frequency monitor	Monitors Synthesizer’s frequency ramp by counting (divided-down) clock cycles and comparing to ideal frequency ramp. Excess frequency errors above a certain threshold, if any, are detected and reported.
20	Ball break detection for TX ports (TX Ball break monitor)	IWR2243 architecture supports a ball break detection mechanism based on Impedance measurement at the TX output(s) to detect and report any large deviations that can indicate a ball break. Monitoring is done by TIs code running on BIST R4F and failure is reported to the host. It is completely up to customer SW to decide on the appropriate action based on the message from BIST R4F.
21	RX loopback test	Built-in TX to RX loopback to enable detection of failures in the RX path(s), including Gain, inter-RX balance, etc.
22	IF loopback test	Built-in IF (square wave) test tone input to monitor IF filter’s frequency response and detect failure.
23	RX saturation detect	Provision to detect ADC saturation due to excessive incoming signal level and/or interference.

(1) Monitoring is done by the TI's code running on BIST R4F. There are two modes in which it could be configured to report the temperature sensed via API by customer application.

Report the temperature sensed after every N frames
Report the condition once the temperature crosses programmed threshold.

It is completely up to customer SW to decide on the appropriate action based on the message from BIST R4Fvia Mailbox.

(2) Monitoring is done by the TI's code running on BIST R4F.
There are two modes in which it could be configured to report the detected output power via API by customer application.

Report the power detected after every N frames
Report the condition once the output power degrades by more than configured threshold from the configured.

It is completely up to customer SW to decide on the appropriate action based on the message from BIST R4F.