• State TI Thinks Resolved
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 34 subscribers
  • Views 63 views
  • Users 0 members are here
Support feedback
Options
Options
Related

TCA9517-Q1: I2C Not Working Properly

Mesut KILIÇ
Prodigy 170 points

Part Number: TCA9517-Q1
Other Parts Discussed in Thread: TCA9517, MSPM0G3519

We have the system that shown down below. We are having a I2C communication issues. TCAL devices works as expected but, TMAG devices does not work properly. We try to read data from tcal devices but the data we get back is wrong or currupted.

We are supplying tmag devices thrugh the tcal device. Tmag devices enabled one by one and changing i2c address.

What is wrong on our system design? What are we doing wrong?

  • 0
    TI__Guru 56151 points

    Hi Mesut,

    To narrow down on root cause, it would be helpful to provide the full schematic of the TCA9517, as well as the waveforms at A/B side of the device. One thing to keep in mind is that the pull-ups on B side should be sized accordingly, to ensure that a VIL back into the device at this side is less than 0.4V:

    Regards,

    Jack

  • 0 in reply to Jack Guan
    Prodigy 170 points

    Hi Jack,

    I tested only the sensor side with STM32 NUCLEO-G474RE to ensure sensors are working. The sensors worked just fine with 2K2 pullup resistors at both 100kHz and 400kHz I2C frequencies. But one sensor was not working. After investigation we determined that one sensor's SCL and SDA lines were soldered in reverse. 

    After fixing the sensor connection our system worked at 100kHz. But not worked properly at 400kHz. 

    R63 and R64 not populated. 2k pullup resistor soldered between 3V3.GR1 and SCL, SDA lines.

    C1: Sensor Side, C2: Host Side

    100KHz SDA Line

    400kHz SDA Line

  • 0 in reply to Mesut KILIÇ
    TI__Guru 56151 points

    Hi Mesut,

    Can we attempt to retest with stronger pullups, i.e 1kohms? 

    Mesut KILIÇ said:
    I tested only the sensor side with STM32 NUCLEO-G474RE to ensure sensors are working. The sensors worked just fine with 2K2 pullup resistors at both 100kHz and 400kHz I2C frequencies.

    What is the difference between this board that allowed for 100KHz/400KHz operation vs. the board that does not allow it to function? 

    Mesut KILIÇ said:
    After fixing the sensor connection our system worked at 100kHz. But not worked properly at 400kHz. 

    Regards,

    Jack

  • 0 in reply to Jack Guan
    Prodigy 170 points

    Hi Jack,

    Jack Guan said:
    Can we attempt to retest with stronger pullups, i.e 1kohms? 

    I have tested with NUCLEO-G474RE and 1K pullup resistor. Sensor side working fine with 400kHz. Here is the waveforms:

    Jack Guan said:
    What is the difference between this board that allowed for 100KHz/400KHz operation vs. the board that does not allow it to function? 

    On our system, we are using MSPM0G3519 as a master MCU and we have TCA9517 in between MCU and Sensor Side. On the test setup we have NUCLEO-G474RE as a MCU and directly connected to sensor side with pullup resistors.

    I can be sure that the sensor side is working. The  problem may be on the MCU side or on the TCA9517 side.

    How should I proceed?

    Thanks

  • 0 in reply to Mesut KILIÇ
    TI__Guru 56151 points

    Hi Mesut,

    As the board with the MSPM0G3519 is functioning and NUCLEO-G474RE is not, it would indicate that investigation on the second MCU should looked further. From the waveforms, the rise times are a bit slower (which can be remedied with using stronger external pullups), though I do not see anything alarming on the waveforms which you provided (i.e false logic high/low signal), otherwise please help to clarify the specific concern is. 

    Regards,

    Jack