UCD90160A: [Consultation] TI - UCD90160A (SEQUENCER) Alert pin default status is "L" when power up sequence normally be operated

Hi Yihe,

I noticed the results you mentioned are related I2C communication.

All rails are normally operated, there is only communication problem in the beginning, and I need to clear logged faults (figure1) to de-assert "PMBALERT_N" from L to H level (figure2).

(1) Is there any default I2C/SMBus (like congenital defects) communication problem when system boot up in the beginning ?

(2) How can I prevent from this kind of CML fault logs in UCD90160A in the beginning when rails are all ok ?

Thanks a lot.

Figure1:

Figure2:

Best Regards,

Paul Lei

Hi Yihe,

1. However, we have same design in other components with ALERT_N signal, SDA/SCL are all pulled-up to P3V3 which is the same voltage source to UCD90160A, and they won't assert ALERT_N signal to L, is there any other design requirements (HW / FW) in UCD90160A I haven't noticed ?

2. OK, got it, if we have this default assertion value, host can issue clear status (0x03h) command to reset this ALERT_N to H.

Thanks.

Best Regards,

Paul Lei

Hi Yihe,

For debugging of software, you mean it's to fix the configuration file in UCD90160(A) or the FW setup on my system.

However, I don't connect any host on my system in the beginning, but it still occurs CML fault in logs and causes ALERT_N pin assertion.

Thanks.

Best Regards,

Paul Lei

HI

I mean your host i2C software.

Please clarify what kind of CML fault. there are many faults embedded in the CML.

if you do not have a host, i won't expect any I2C communication on the bus. have you probed the SCL/SDA?

Regards

Yihe 

Hi Yihe,

No, it's because that we all use same design in other IC for I2C communication, so I just wondering about whether there is default communicated issue in UCD90160(A) in the beginning.

Thanks.

Best Regards,

Paul Lei

Hi Yihe,

Can you talk more about 03h REG, clear fault command ?

I have seen some descriptions in datasheet (slua815b), UCD90160(A) doesn't support SMBALERT_N MASK function.

Can you help to check with your EVBoard for this alert pin (SMBALERT_N) status after powering up ?

Thanks.

Best Regards,

Paul Lei

Hi Yihe,

Got it and thanks.

I'll try to investigate other devices on same I2C bus path which might affect UCD90160(A).

One thing about fault I want to confirm again, when fault is cleared by 03h (clear fault command) to UCD90160(A), it won't let device restart, right ?

It should be cycled UCD90160(A) power supply or applied with retry mode to restart rails again, right ?

Thanks.

Best Regards,

Paul Lei