There is an issue with the sleep process of tja1145, causing MCU to restart

[TerrorBlade]

Hi,experts

After entering sleep mode, the INH pin of TJA1145 will enter high ohmic;

At present, the program flow is that after TJA1145 enters sleep, fs26 (controlling the power supply of MCU) enters sleep mode through SPI command after configuring wake1 pin wake-up (because INH is connected to wake1 of fs26, only wake-up can be controlled and sleep cannot be controlled through INH);

According to the current process, the MCU will restart. Initially, I suspected that it would take time for the INH pin to reach high ohmic, so I added a delay between TJA1145 entering sleep and FS26 entering sleep. However, no matter how long I set the delay, it will still restart; Later, I tried to turn off the VCC of TJA1145 and then enter sleep mode, which hardly required any delay to avoid restarting;

My question is:

1.Is the change in the status of the INH pin the cause of MCU restart?

2.Why can shutting down VCC effectively avoid restarting?

3.Is the above process reasonable?

[JozefKozon]

Hi Jin,

please share your schematic with voltage levels and part values. Please note, that you can set the TJA1145 can be set to Standby mode, which is same as the Sleep mode, except that the INH pin remains active.

If you need a delay for setting the INH pin high impedance, you can set the TJA1145 first to Standby mode and later to Sleep mode.

With Best Regards,

Jozef