DS90UB933-Q1: 0x01 Power and Reset

Hi Jiashow,

Are you serious? Even though there are a lot of descriptions for VDDIO at 2.8V in the datasheet?

Regards,

Oguri

Hi Jiashow,

Please answer my questions. The customer connected VDDIO to 2.8V from the beginning. My questions are about bit 4 and 5 of 0x01 "Power and Reset" register:

Bit 4: Which of 1.8V and 3.3V configuration is more suitable for 2.8V IO case?

Bit 5: How does this function work?

Regards,

Oguri

Hi Oguri,

Please give me a couple days to find this out internally for you.

Hi Jiashow,

Thank you for the update. I will be waiting for your final answer.

Regards,

Oguri

So, you mean bit 4 should be configured as 1.8V for 2.8V VDDIO case?

Thanks.

Oguri

Hi Jiashow,

The customer's configuration for bit 4 is 3.3V but VDDIO is 2.8V. This is opposite to your recommendation. What bad effect is possible with the customer's setting? Such as VIH is too high for 2.8V signal?

Actually, this may have caused a serious problem. 

Thank you.

Regards,

Oguri

Hello Oguri,

why is the customer setting this register? Normally they should keep auto detect ON, and do not change and settings here!!

Hi Hamazeh,

The customer's setting is default. Both bit 4 and 5 are "1".

Is this the recommended setting for VDDIO 2.8V case?

In this setting is the below statement true?

    "Auto Voltage Control (bit 5) overrides bit 4. So, the setting of bit 4 is meaningless."

 Thanks!

Oguri

HI Jiashow,

The customer still need a detailed explanation about the bit 5 "V(VDDIO) Control" of 0x01 "Power and Reset". Please explain how it works. Especially how it detects the VDDIO voltage and what the resultant configuration will be.

Thanks!

Oguri

Hi Jiashow,

The customer wants a explanation how it works, because there is no information in the datasheet. Please explain it.

Thanks!

Oguri