DS90UB953-Q1: 1% failure rate when writing 0x02 to 0x01 register after power up

Hao Wang14

Part Number: DS90UB953-Q1

Hi Team,

It's found that there is about 1% failure rate when writing 0x02 to 0x01 register of 953 after power up, because the GPIO1 is not pulled up and the sensor connected with 953 is not powered up, but the registers 0x0E and 0x0D are all configured successfully.

However, if 953 is not reset after power up, the sensor can always work normally.

So my questions are:

1. What will happen when writing 0x02 to 0x01 register of 953? Is there any unexpected effect by doing so?

2. Should 953 always be reset after power up? Per my understanding, it's not necessary to have 953 reset because 953 will go to default settings after power up.

Thanks and Best Regards!

Hao

over 4 years ago

0 Hamzeh Jaradat over 4 years ago

TI__Guru** 107970 points

Hello Hao,

why are you resetting the 953 after power up? And why using 0x02 in reg 0x01, why not using 0x01 in reg 0x01?

0 Hao Wang14 over 4 years ago in reply to Hamzeh Jaradat

TI__Expert 4415 points

Hi Hamzeh,

Customer is not sure if they need to reset 953 or not after power up, that's also my second question, so we want to get confirmation from you.

1. Should 953 always be reset after power up? According to your reply, it seems to be not necessary.

2. If the answer for item 1 is yes, should 0x01 be written? Why not 0x02?

Thanks and Best Regards!

Hao

0 Hamzeh Jaradat over 4 years ago in reply to Hao Wang14

TI__Guru** 107970 points

Hello Hao,

1) No, you do not need any reset.

0 subin li over 4 years ago in reply to Hamzeh Jaradat

Expert 1050 points

Hi, Hamzeh

There is another question, that is, what kind of impact the reset of UB953 will cause.

From the literal meaning of the chip manual, it is just a reset function.

Before the UB953 is configured and the sensor is powered on, I think the reset operation should be a routine operation and should not cause occasional problems.

0 Hamzeh Jaradat over 4 years ago in reply to subin li

TI__Guru** 107970 points

Hello Hao,

If you use 0x02, this will erase all register values and set them to default. So, if you have had initialize any thing in the device, it will be set to default, and you will need to initialize the device again.

Any digital reset of the device will lead to losing the link shortly.

0 subin li over 4 years ago in reply to Hamzeh Jaradat

Expert 1050 points

Hi, Hamzeh

This is in line with our expectations.

Our operation is to power off and restart, then reset the UB953, and then initialize the device again.

But this will cause some occasional problems, sometimes I2C timeout occurs when communicating with sensor through UB953.

If we don't reset UB953, this will not happen.

0 Hamzeh Jaradat over 4 years ago in reply to subin li

TI__Guru** 107970 points

Hello Subin,

If you are following the power-up sequence from the data sheet, No reset is required.

0 Hao Wang14 over 4 years ago in reply to Hamzeh Jaradat

TI__Expert 4415 points

Hi Hamzeh,

Customer will follow your suggest without using RESET after power up. However, do you happen to know when there is about 1% failure rate when writing 0x02 to 0x01 register of 953 after power up? Because it's very weird...

Thanks and Best Regards!

Hao

0 Hamzeh Jaradat over 4 years ago in reply to Hao Wang14

TI__Guru** 107970 points

Hello Hao,

No, I am not aware of any failure when reseting the device. This is not expected behaviour.

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DS90UB953-Q1: 1% failure rate when writing 0x02 to 0x01 register after power up