JAJSIR5C October 2019 – October 2023 TPS65313-Q1
PRODUCTION DATA
The device enters the DIAGNOSTIC state when one of two conditions occur. The first condition is from the RESET state after the NRES extension, if the device error counter (DEV_ERR_CNT) is equal to or less than the threshold value for the SAFE state lock (SAFE_LOCK_TH). The second condition is from the SAFE state after the system MCU sends the SAFE_EXIT SPI command.
All monitoring and protection functions stay enabled in the DIAGNOSTIC state. The following events occur as the device goes into the DIAGNOSTIC state:
The primary purpose of the DIAGNOSTIC state is for the system MCU to perform the device and system-level diagnostics prior to enabling or configuring the primary system protection functions listed in Section 11.9. If any diagnostic test fails, the system MCU can command the device to go to the OFF state by clearing the wake-up latch (by sending the CLR_WAKE_LATCH SPI command).
The system MCU changes the device configuration registers only when the device is in the DIAGNOSTIC state and when the write-lock protection is removed by executing the CLR_CFG_LOCK command. The device configuration registers are also protected by CRC. When the desired configuration is set, the system MCU must write the expected configuration CRC value (DEV_CFG_CRC in SAFETY_DEV_CFG_CRC register) and enable the configuration CRC.
If the device stays in the DIAGNOSTIC state for the time-out interval and the DIAGNOSTIC state (tDIAG_STATE_TO), the device goes into the SAFE state and the DIAG_STATE_TO status bit is set. Therefore, all device and system-level diagnostics must be completed within the tDIAG_STATE_TO time. To support software development, however, the TPS65313-Q1 device allows the user to mask the DIAGNOSTIC state time-out event and to keep the device in the DIAGNOSTIC state. This ability is achieved through the DIAG_EXIT_MASK SPI bit which can be set by the MASK_DIAG_EXIT command.When DIAG_EXIT_MASK bit is set to 1b device transitions to RESET state if WD_RTS_EN bit is set to 1b and accumulated watchdog failure counter (WD_FC) reached watchdog reset threshold value WD_FC_RST_TH.
While the device is in DIAGNOSTIC state the WD TIME_OUT event can be used by the MCU application software (SW) to establish synchronization between the device and MCU SW and HW processes. Each WD TIME_OUT event is followed by the start of a new WD Q&A sequence run. Another way to synchronize the MCU and the device WD function is updating the device WD configuration or WD window duration. Each watchdog configuration update increments the WD_FAIL_CNT[3:0] counter by 1, followed by the start of a new WD Q&A sequence run. All events that trigger new WD cycle start are covered in WD Function Initialization Table 11-13. Default setting for WD_RST_EN bit is 1b.