• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 33 subscribers
  • Views 582 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65987D: Slave Address Index

K.Yaita
Guru 29720 points
Part Number: TPS65987D
Other Parts Discussed in Thread: TPS55288

Hi Team,

My customer considers using TPS65987D and TPS55288 as the following application note shows.
https://www.tij.co.jp/jp/lit/an/slvaeq7/slvaeq7.pdf

Regarding Figure 4, I believe the value of "Slave Address Index" will be added to the rightmost bytes of "Data".
If we set 1 for "Slave Address Index" and 0xd200 for "Data", we can access the register of I2C address=1h.
Is my understanding correct?

Best Regards,
Yaita

  • +1
    TI__Genius 9630 points

    Hi Yaita-san,

    You will put the slave address in a different register, register 0x64. In this app note in register 0x64, the Index 0 slave address is 0x74. And there is a typo in this figure. The data length should be 2, as there are two bytes of data in the data section. If you probe the I2C lines with an I2C decoder like Saleae, you would see the following:

    0x74 0x00 0xd2

    Thanks,

    Emma

  • 0 in reply to Emma Hoying
    Guru 29720 points

    Hi Emma-san,

    Thank you for your support.

    >In this app note in register 0x64, the Index 0 slave address is 0x74.
    Do you refer "Slave 1 Configuration" is selected if we set "Slave Address Index=0"? 
    If so, I also believe  "Slave 2 Configuration" is selected if we set "Slave Address Index=1".
    Is my understanding correct?

    Best Regards,
    Yaita

  • +1 in reply to K.Yaita
    TI__Genius 9630 points

    Hi Yaita-san,

    You are correct, the indexing of the slave address start at 0. For your example, it looks like this:

    Index 0 = Slave 1 Configuration

    Index 1 = Slave 2 Configuration

    Thanks,

    Emma

  • 0 in reply to Emma Hoying
    Guru 29720 points

    Hi Emma-san,

    Thank you for your continuous support.
    I understand.

    By the way, you referred there is a typo in Figure 4.
    --------------------------------------------------------

     And there is a typo in this figure. The data length should be 2, as there are two bytes of data in the data section. If you probe the I2C lines with an I2C decoder like Saleae, you would see the following:

    0x74 0x00 0xd2

    --------------------------------------------------------
    I think it is not a typo because TPS55288 supports Multi-byte Write and REF Register's address is 0h and 1h.
    What do you think about it?





    Best Regards,
    Yaita

  • 0 in reply to K.Yaita
    TI__Genius 9630 points

    Hi Yaita-san,

    Could you use an I2C analyzer, such as Saleae, in order to capture what you are seeing on the I2C lines so we can confirm the data length?

    Thanks,

    Emma

  • 0 in reply to Emma Hoying
    Guru 29720 points

    Hi Emma-san,

    My customer hasn't confirmed with the actual board yet.
    It is just a study phase for my customer.
    Okay, I will contact you again if we need your further support when he confirmed the actual operation.

    Best Regards,
    Yaita