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Interfacing TPS65381 With RM48x

Part Number: RM48L950
Other Parts Discussed in Thread: RM48L952, TPS65381-Q1, TPS65381A-Q1

Hi Ti,

We are working on the safety application. We want the watchdog circuit to cover high diagnostic. The safe TI library has the TPS driver library and we have some doubts about it.

1. Whether TPS65381 companion chip covers high diagnostic coverage like voltage monitoring and watchdog circuit.

2. The SPNA176A document helps on Interfacing TPS65381 With Hercules (RM46). These documents tells to use the ecmp_if.c and ecmp.c as source files. But the latest safety ti diag library (2.4.0) has no file available in the name ecmp_if.c and ecmp.c. Whether the source file available in safe ti library (2.4.0) TPS driver library is the latest one for RM48 series. If yes, is there any documentation available like SPNA176A?

3. How does the TPS65381 chip work as the Watchdog monitoring circuit?

4. In the rm48l952 TPS test example application, how does the watchdog is serviced?

5. What is the window watchdog and Q&A watchdog in TPS65381? Is it implemented the same in the demo application?

6. Whether the ERROR/WDI of TPS65381 is used for watchdog trigger input or MCU ESM in the demo application?

7. Whether the TPS chip monitors the voltage continuously and triggers the nPORST pin when the voltage falls above or below the threshold limits? Or does the SW needs to poll the VMON status continuously and take appropriate action?

8. In the custom application, whether the TPS should work in ACTIVE or DIAGNOSTIC state?

9. For the following safe diagnostics like voltage monitoring, oscillator check, window watchdog, temperature shutdown and etc, whether the NRES will be triggered, if any fail condition occurs?

 

Thanks and Regards,

Monish P

  • Hi Monish,

    1. Yes. TPS65381 monitors the power rails, and monitor the code execution using its QA window watchdog.

    2. I suggest to use the APIs of the Safety Diagnostic Library

    3. TMS65381 has a built-in QA window watchdog.

    4. TMS570 services the watchdog through SPI interface. 

    5, 6.  Please refer to TPS65381 user guide. The ERROR/WDI pin can be configured as an input for TMS570 ESM nERROR signal monitor.

    7. The TPS monitors the power rails continuously and asserts the nRES signal which might be connected to TMS570 nPORRST

    8, 9. TPS65381 has several states: reset, diag, active, safe, etc. Please refer to chapter 5.4 of the datasheet

    You can use power management forum for any questions regarding the TPS65381

  • Hi Monish,

    1. Yes. TPS65381 monitors the power rails, and monitor the code execution using its QA window watchdog.

    2. I suggest to use the APIs of the Safety Diagnostic Library

    3. TMS65381 has a built-in QA window watchdog.

    4. TMS570 services the watchdog through SPI interface. 

    5, 6.  Please refer to TPS65381 user guide. The ERROR/WDI pin can be configured as an input for TMS570 ESM nERROR signal monitor.

    7. The TPS monitors the power rails continuously and asserts the nRES signal which might be connected to TMS570 nPORRST

    8, 9. TPS65381 has several states: reset, diag, active, safe, etc. Please refer to chapter 5.4 of the datasheet

    You can use power management forum for any questions regarding the TPS65381

  • Hi Wang,

    Thanks for the reply.

    The TPS65381-Q1 details show "NOT RECOMMENDED FOR NEW DESIGN", is TPS65381A-Q1 is the alternative/replacement for TPS65381-Q1?

    2. Also, whether the TPS driver API is common for both TPS65381A-Q1 and TPS65381-Q1 chips?

    3. Whether the TPS chip will be able to meet the diagnostic measure of 99% provided as per the IEC-61508 standard?

    Regards,

    Monish P

  • Hi Monish,

    1. You are correct. The TPS65381A-Q1 should be used for the new design.

    2. Yes, it is same.

    3. Please check with power management team to download the safety manual and FMEDA for TPS65381