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TPS25751: How to access registers

Motoyasu Hattori
Genius 10945 points
Part Number: TPS25751

Tool/software:

Hi,

If my customer wants to read data from memory-mapped registers (Ex. PD status [40h]),  is it correct to access it as follows?

Access Format : Figure8-31 on the datasheet.

  • Unique Address = define from ADCIN1/IN2 on Table 8-5.
  • Register Number = 40h  (PD Status register)
  • Byte Count = 4
  • Read 4-byte

Also, if they want to write "SWDF" 4CC_command, is it correct to access it as follows?

Access Format : Figure 8-30 on the datasheet.

  • Unique Address = define from ADCIN1/IN2 on Table 8-5.
  • Register Number = 08h  (Command Register)
  • Byte Count = 4
  • Write 'SWDF' (0x53574446) as data

I want to confirm whether my understanding is correct 

Thanks and best regards,
M.HATTORI.

  • 0
    TI__Mastermind 37855 points

    Hi M. Hattori,

    Your understanding is partially correct.

    Motoyasu Hattori said:

    Access Format : Figure8-31 on the datasheet.

    • Unique Address = define from ADCIN1/IN2 on Table 8-5.
    • Register Number = 40h  (PD Status register)
    • Byte Count = 4
    • Read 4-byte

    For the I2C read, they will first send the unique address with the register number, then will send the unique address with the read bit. The PD controller will then return 1 + N bits, where the extra byte is the Byte count that is returned first.

    In your example, the PD status is 4 bytes long

    • Unique Address
    • Register Number
    • Unique Address (read)
    • Read 5-bytes (the first being the num bytes, and the following 4 being the data)

    For the 4CC command, you are correct.

    Thanks and Regards,

    Chris