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TPA6404-Q1: Read all return as zero when i run AC load diagnostics

user5927240
Prodigy 30 points
Part Number: TPA6404-Q1

I use TPA6404 in my design,

when i run load diagnostics with the step listed in chapter 9.3.6 of TPA6404's datasheet, i found the result of dc load diagnostics and line output diagnostics is related to my actual hardware, but the result of ac load diagnostics are all zero, i have no idea about this now, need help.

herre is my step:

......other......

......dc load diagnostics......

first i read all regs checked, all are same with default value listed in datasheet

0x80->reg 0x16;    0x32->reg 0x2A;    0x08->reg 0x15;

wait reg 0x0F show CH1 change to Hi-Z mode

read reg 0x1B and reg 0x1C

0x80->reg 0x16;    0x32->reg 0x2A;    0x02->reg 0x15;

wait reg 0x0F show CH3 change to Hi-Z mode

read reg 0x1B and reg 0x1C (i  justread 0)

set CHx into Hi-Z mode(reg 0x04);    0x00->reg 0x16;    0x32->reg 0x2A;     set CHx start AC load diagnostics(reg 0x15)

wait reg 0x0F show CHx change to Hi-Z mode

read reg 0x1B~0x1E  (i  justread 0)

red reg 0x17~0x1A  (i  justread 0)

......other....

btw, i did'nt find  "AC diagnostic mode" bit in tpa6404's reg list. so i just use "DC diagnostics mode" (reg 0x0F)

When the test is complete the channel reporting register indicates the status change from the AC diagnostic
mode to the Hi-Z state. The detected phase is stored in the appropriate I2C register when the device transitions
to the Hi-Z state.

  • 0
    TI__Genius 9140 points
    Hi,

    I can't find anything abnormal in the steps. Below is the steps i was using to do a quick verify.

    w 54 00 80 #reset device
    d 100 #delay 100ms, wait device reset
    r 54 00 20 #read registers

    w 54 16 00 #AC diagnostic setting
    w 54 2A 32
    w 54 15 02 #AC diagnostic setting, enable channel 3

    d 500 #use delay 500ms to replace checking 0x0F register
    r 54 00 20 #Read registers
    w 54 15 00 #disable AC diagnostic


    And at same time, please check if the STANDBY pin is high. If that pin is low, the device analog circuit is shutdown and the AC function will not work, even though IIC read/write is functional.




    Dylan
  • 0 in reply to Dylan Yao
    Prodigy 30 points

    Thank you very much, i use delay 500ms to replace checking 0x0F register, and it works.

    there is still a question about  channel reporting register, dose the "AC diagnostic mode" means 11 in reg 0x0F?

    "When the test is complete the channel reporting register indicates the status change from the AC diagnostic mode to the Hi-Z state"

  • 0 in reply to user5927240
    TI__Genius 9140 points
    Yes, it is 11 in 0x0F register.
  • 0 in reply to Dylan Yao
    Prodigy 30 points
    OK, i can use delay 500 ms this time and check what's wrong with 0x0f register later, thanks!