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TPS659037: I2C bus protocol

Takeshi Sasaki
Expert 4480 points
Part Number: TPS659037

Hi team,

Could you tell me how to access register through I2C? The datasheet shows address (7bit) R/W (1bit) ACK (1bit) Data?(8bit) ACK (1bit), in Figure 5-14.  I assume page selection is included the address (7bit). So, for example, in order to access BACKUP1 in power registers, what the I2C bus protocol is like? For example, 0x58 (page selection) + R/W + ACK + 0x19 (address) +  data + ACK + START/STOP?, or  0x58 (page selection) + R/W + ACK + dummy data + 0x19 (address) + data + ACK + START/STOP or something else?

Thank you for your support.

Best regards,

Takeshi Sasaki

  • 0
    TI__Genius 10000 points

    Sasaki-san,

    yes, the page is decided by which I2C address is chosen. 0x58 will chose page 1.

    You would need to send the I2C address (0x58) + R/W, then the 8-bit data and the stop/start condition. These are sent on the SDA line. The SCL line should produce the acknowledge bits.

    See https://www.nxp.com/docs/en/user-guide/UM10204.pdf for details on I2C format.

    Thanks,

    Nastasha

  • 0 in reply to Nastasha
    TI__Expert 4480 points
    Hi Nastasha,

    Thank you for your comments. What is the mean of 8-bit data that you mentioned above? In my understanding, sending 0x58 can select page 1 (=power registers), it means you can select one of power registers, such as BACKUP1(e.g. address: 0x19, default data: 0x0). How to designate the register through I2C protocol exactly? I assume you should send addresses of 0x58 and 0x19 through I2C protocol, but how?

    Best regards,
    Takeshi Sasaki
  • 0 in reply to Takeshi Sasaki
    TI__Genius 10000 points
    Sasaki-san,

    You need to send the I2C address (0x58), then R/W bit.

    If reading, you specify the register address (0x19)
    if writing, you specify the register address (0x19) then the data you want to write to that register.

    For questions about the I2C protocol, please reference the I2C manual in the link above.

    Thanks,
    Nastasha