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TPS65216: Register write

Part Number: TPS65216
Other Parts Discussed in Thread: TPS6521815

Customer uses TPS65216 now and find a problem.

Customer changed DCDC2 register to 0xA4. RD thinks he has written it successfully because the read back value and the output voltage are able to be changed.

What customer did is:

  1. Write Register SELW (0x1A) = 0xC6 (set Go bit)
  2. Write Register PASSWORD (0x10) = 0x17 ^ 0x7D, for writing DCDC2
  3. Write DCDC2 (0x17) = 0xA4
  4. Read DCDC2, check if it equals 0xA2

However, after power on reset, DCDC2 becames 0x99 again.

Do I need to write additional registers to enable EEPROM backup function?

 

Customer mentioned, there is no problem with chip revision 4.  however this time they got revision 2.1 chip and find problem. Is there any difference could cause this problem?

Regards

Brian W

  • Hi Brian,

    This thread has been assigned to device expert. Expert is based in USA and they have independence day today so please allow a delay over weekend.

  • Brian Wang0928 said:
    1. Write Register SELW (0x1A) = 0xC6 (set Go bit)
    2. Write Register PASSWORD (0x10) = 0x17 ^ 0x7D, for writing DCDC2
    3. Write DCDC2 (0x17) = 0xA4
    4. Read DCDC2, check if it equals 0xA2

    Step 1 is meaningless. Setting the GO bit instantaneously allows DCDC1/2 to transition from the beginning voltage (0x99 = 1.1V) to the new voltage. In this case, they are both 0x99 = 1.1V so no transition would occur.

    In Step 3, you write 0xA4 to the DCDC2 register. Why would you read back to verify that the value is 0xA2 in Step 4? If you set it to 0xA4, it should stay as 0xA4 and not spontaneously change to 0xA2.

    Brian Wang0928 said:
    However, after power on reset, DCDC2 becames 0x99 again.

    This makes sense to me. In order to re-program the non-volatile EEPROM memory, you need to execute the Programming procedure:

    Programming Power-Up Default Values: A consecutive write of 0x50, 0x1A, or 0xCE to the password register (0x10) commits the current register settings to EEPROM memory so they become the new power-up default values.


  • Thanks.

    Where the material i can get the flowchart of programming procedure you showed? i didn't find it in d/s.

    Regards

    Brian 

  • Brian,

    Please refer to TPS6521815, which is the full-featured programmable version of TPS65216. The digital core and the implementation of EEPROM programming are the same for both devices.

    We will need to update the TPS65216 datasheet to include programming section, but it takes time and I cannot guarantee a delivery date.