TPS65381A-Q1: STATE change from STANDBY to RESET

Hi Shinichi,

I have copied your questions and inserted the answers below and pointed you to further details in the datasheet. Please let us know if you have other questions. 

Q1: Datasheet P.27 of Table 5-2 Internal Error Signals (NAVDD_UV, BG_ERR1,.....,LOCLk) ,

when the TPS65381 detects an error, the TPS65381 is reset itself, and then change the state to STANDBY or RESET.

If it return from abnormality, is it possible to confirm a restart by communicating by MCU.

A1: Table 5-2 is a summary of internal error signals and provides a list of what happens to the device for each of those detected errors.  However the best place to see a full view of the operating state changes is in section 5.4.19 Device Operating States, Figure 5-16. Device Controller State Diagram.  From the state diagram the priority of state changes is also shown if two or more errors are detected.  It also shows how the device will "restart" if it is put into STANDBY (if IGN or CANWU is high).  Not all detected errors will cause state transitions as is outlined in Table 5-2.  Sections 5.4.20 through 5.4.25 also provide additional details on the states, state transitions and events that cause transitions into and out of the states.

Q2: According to a datasheet, the information are stored by resister of TPS65381 once, but they are cleared after a certain period of time has elapsed. For example, it is described BG_ERR1 of VMON_STAT_1,"-Cleared to 0 if an overvoltage condition is no longer present". There are many cases. I think since it is not possible to know the time to clear 0, there is any way to know about MCU.

A2: The duration of a fault is not known.  If the fault is one that causes a transition to RESET state or STANDBY state, NRES would be low during the fault and the MCU will be held in RESET or unpowered. 

Q3: I'd like to know how to know return from the error, if possible.

I am considering after error is detected, MCU will be halt except power restart.

I think the STATE changes to STANDBY, then changes to RESTART to output MCU reseting automatically.

Is it correct?

Or STANDBY to RESET STATE is only after a wake-up request from ignition (IGN pin = high,

deglitched IGN bit = 1) or CANWU pin (CANWU pin = high, deglitched and latched CANWU_L bit = 1).

In this case, is it possible to confirm error resister,

A3: Please see Table 5-2 and Figure 5-16. Device Controller State Diagram for which detected error causes which state transition.  If the detected error caused RESET state, the TPS6581A-Q1 will transition to RESET state (pull NRES low to MCU) and will transition to DIAGNOSTIC state after the error is cleared and the reset extension time has expired. If the detected error caused STANDBY state, the TPS6581A-Q1 will transition to STANDBY state (pull NRES low to MCU).  The device will transition to RESET state after the error is cleared and IGN or CANWU pin is high.  Most status bits are self clearing after the fault is removed, so if the error caused a transition to RESET or STANDBY which will cause the MCU to reset the MCU will not be able to see these bits when it re-boots after the fault is removed.  Some configuration bits are re-initialized after RESET state.  All configuration bits are re-initialized after an NPOR event, see section 5.4.26 Power on Reset (NPOR) for details.  These are summarized for each register in section 5.5.3 SPI Registers (SPI Mapped Response).  For each register the initialize source is listed. 

Best Regards,

Scott