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TPS23861: TPS23861 I2C Issue

Tongfu Song
Prodigy 50 points
Part Number: TPS23861

Hello,

Here's one problem:

Only supply 3.3V currently for test, the Signal Level of SDA(TPS23861) is always low, therefore, we cannot access it by i2c bus.

The reset and shutdown both are high level.

Could you give some ideas for this?

PS: Could you show me the correct waveforms of SDA/SCL for reference?

Thanks. 

  • 0
    TI__Genius 15685 points

    Hi Tongfu,

    Did you supply power to Vpwr? TPS23861 need both Vpwr and VDD to be full functional. And You will need also to follow power on sequence described in this app note. Thanks.

    Best regards,

    Penny 

  • 0 in reply to Penny Xu
    Prodigy 50 points

    Hi Penny,

    Thank you firstly. 

    Currently, provide the both power the TSP23861, the I2C control is ok

    However, we only get 'Input Voltage (0x2E 0x2F)' and 'Device ID (0x43)'; cannot get the correct data from 0x30 to 0x3F, the feedbacks are always zero no matter if the PD is connected or not.

    So could you give some suggestions?

    Thanks,

  • 0 in reply to Tongfu Song
    TI__Genius 15685 points

    Hi Tongfu,

    Can you check if the port is turned on when you connect a PD to the port? While nothing connected, it is expected to get all zeros from register 0x30 to 0x3F.

    Can you send me your settings of registers from 0x00 to 0x20? And it is good to have a waveform showing voltage between Vdrain and GND when you connect your PD. Thanks.

    Best regards,

    Penny

  • 0 in reply to Penny Xu
    Prodigy 50 points

    Hi Penny,

    Can you check if the port is turned on when you connect a PD to the port? --> Yes, the connected port can supply power to IP-Camera

    While nothing connected, it is expected to get all zeros from register 0x30 to 0x3F. --> But we get all zeros when we connected to IP Camera

    Here're the datas from 0x00 to 0x20: they are all same no matter the IP Camera conencted or not

    08 f4 00 00 0f 0f 00 00 00 00 00 00 08 08 08 08 00 a0 ff 0f 

    IC mark:

    Waveform showing voltage between Vdrain and GND when you connect your PD --> Here's the waveform

  • 0 in reply to Tongfu Song
    TI__Genius 15685 points

    Hi Tongfu,

    Your status register 0x0C to 0x0F value(0x08) shows there are MOSFET fault happening on all ports. Please check the MOSFETs and replace the MOSFETs and try again. Thanks. 

    Best regards,

    Penny 

  • 0 in reply to Penny Xu
    Prodigy 50 points

    Hi Penny,

    Thanks for your suggestions.

    We've figured out the issue and can get all the values of registers correctly.

    The casue for this issue is that we add one more nmos used as mode A and B swith, this affects the tps23861 to turn on the origianl mosfet.

    Thanks.