DS90UB913A-Q1: DS90UB913A-Q1 can not be reset

Jerry
What was the input power dropped to? Chip is normally reset using PDB pin (or in Register map using I2C)

Hi Vijaya

I'm not sure the power supply voltage (VBAT) dropped to, which changes during the whole testing procedure.
913A is at remote side, and no MCU. We can not control its PDB pin (NO GPIO connect to this pin).
And if 913A did not POWER ON RESET correctly, how 914A can communicate with 913A via I2C, and change Register map?
Thank you.

Jerry,

1. please check the UB913a's external PDB design, what R and C are used here? in general application, the PDB sequence is controlled by this RC.

2. how do you judge the PDB is NOT correct? in general, you need measure it with passive probe.

3. UB913a register 0x01[0:1] reset function can be supported with remote I2C control.

best regards,

Steven

Hi Steven,

1.      Please check the UB913a's external PDB design, what R and C are used here? in general application, the PDB sequence is controlled by this RC.

-> The schematics is below. R=10K, C=10uF, and I add voltage supervisor this time.

2.      How do you judge the PDB is NOT correct? in general, you need measure it with passive probe.

-> I don’t know PDB is correct or not, just 913A can not reset rightly during the PWRON and PWROFF testing.

3.      UB913a register 0x01[0:1] reset function can be supported with remote I2C control.

-> If 913A can not reset correctly, then 913A can not work, how 914A can communicate with 913A via I2C and control 913A’s reset?

 

Thank you

Jerry

Jerry,
in your test, whether you power on the UB913 module soon after power-off it?
For UB913a module, you should have low enough voltage level in PDB pin to secure its operation. for your case, you can add one more RESET chip to pass this test.

best regards,
Steven

Hi Steven,

Yes, I power it soon after power-off it. but in car application, we can not control the delay time.
I add reset chip in the new design, but I don’t know whether it can work in all situation.

Thank you,

Jerry

Jerry,
if it can meet the power-up sequence based on UB913a d/s, it should have no problem. so when the board is returned, you need test it.

best regards,
Steven