FS26 TRK2_UV

[dingyazhou]

Hello, my FS26 will report TRK2_UV failure at the INIT_FS stage of the chip, so it cannot exit the INIT_FS stage, and the functional safety state machine is stuck. May I ask what is the cause

[Vendrick]

hi how can i use the VCORE to supply the VDD_LV of the MCP5746C

[guoweisun]

So for your FS26 setting TRK2_V_OTP [1:0] = 11 as 5.5V and actually it only has 5V,so it trigger UV threshold,right?

[459021854]

• Hi, have you got the SCH-47651 schematics, if you have, can you share with me. Thanks

[459021854]

Hi, have you got the SCH-47651 schematics, if you have, can you share with me. Thanks

[dingyazhou]

It may be so, but the agent did not provide the documents for OTP configuration when buying the board. The model of FS26 is FS26AMDA0A1, and the model of development board is SCH-47651 REV A1

[guoweisun]

Understand, so you can  test the voltage of VTRK2 to confirm this voltage level and tell me the result.

[guoweisun]

what's the value of TRK2 in your board now? do you test it?

[dingyazhou]

As explained below, TRK2 and TRK1 are both 5V, now TRK2 will have an undervoltage flag to read the FS_OVUV_REG_STATUS register through SPI

[guoweisun]

Could you please share with your schematic?

[dingyazhou]

[guoweisun]

During the initialization phase, you can try to set VMON_TRK2_UV_FS_REACTION [1:0 ] as 00 to disable safety output and RSTB based on register of FS_I_OVUV_SAFE_REACTION2.

Use this method to eliminate the TRK2 UV affect.

[guoweisun]

Can you share the circuit of SCH-47651?

[dingyazhou]

Can you add a wechat for easy communication: 18196548686

[guoweisun]

Please measure the actual value of TRK2 and check whether the short circuit happened or not?

[dingyazhou]

The voltage of TRK2 and TRK1 is 5V, and now it is TRK2 undervoltage fault stuck functional safety state machine. The chip manual has such a sentence:  If the regulator is used as a global pin, outside of the module, it is recommended to not include it in power up sequence and turn on the regulator by SPI, to avoid a stuck in reset condition in case of short circuit.