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TAS5768M RAM hold with power down mode

kyt
Expert 2355 points
Other Parts Discussed in Thread: TAS5768M

Hi,ALL

TAS5768M can got to power down mode by setting Page01,Regsiter0x02,bit0.

 

It should be hold CRAM,IRAM,P0 and P1.

If AVDD and CPVDD were OFF, RAM data is clear?

It is occurred in our situation.

Procedures as below:

1)Power on, device operation is correct.

2)RQPD bit set and go to Powerdown.

3)AVDD and CPVDD is off.

4)Master MCU accesses by I2C,but TAS is not respond.

5)AVDD and CPVDD is on.

6)Clear RQPD bit,and bump ALL register,then CRAM data is reset.

This operation was correct as device specification?

If yes,it is not able to power down AVDD and CPVDD.

Is it correct?

best regars,

kyt

  • 0
    TI__Mastermind 46195 points

    Hello,

    Usually AVDD, DVDD and CPVDD are all tied to a single +3.3V and PVDD and AVCC tied to +24V or so.

    Whenever DVDD is removed, the I-RAM, C-RAM and internal register map is reset.

    If DVDD is kept powered, I-RAM is retained even if reset is performed. However, C-RAM and register map will be cleared to default values.

    So in summary...

    DVDD is removed and reapplied:

    • I-RAM contents are lost.
    • C-RAM is reset to default values.
    • Register settings are reset to default values.

    Device is reset or AVDD is removed and reapplied:

    • I-RAM contents are retained.
    • C-RAM is reset to default values (RSTM or AVDD removal).
    • Register settings are reset to default values (RSTR or AVDD removal).

    Device is set in standby/power down (i.e. RQST or RQPD) or XSMT is cycled:

    • I-RAM contents are retained.
    • C-RAM contents are retained.
    • Register settings content is retained.

    More details are available on these wiki pages:

    http://e2e.ti.com/support/amplifiers/audio_amplifiers/w/design_notes/2845.tas5766m-effects-of-power-cycling-on-memory.aspx

    http://e2e.ti.com/support/amplifiers/audio_amplifiers/w/design_notes/2846.tas5766m-effect-of-xsmt-i2s-rqst-and-rqpd-on-power-consumption.aspx

    Regards,

    J-

  • 0 in reply to J-
    TI__Intellectual 1490 points

    Hi Jorge-san,

    Great summary! we would like to have this description onto TAS5766/68 datasheet.  

    In addition TAS5766/68 have below registers. I expect, in your statements related following registers is that correct?

    Device is reset:

    Means when lose DVdd/AVdd/CPVdd supply and assert internal reset by detecting under voltage. It is not same as RSTR or RSTM on register map.

    Device is set in standby/power down:

    Means set command of RQST/RQPD on register map.

     ********************************************************************

    Page0  0x01 b0  RSTR=1 “Reset mode registers”  

    Mode registers are forced to default value. It is available only Standby mode.

     

    Page0  0x01 b4  RSTM=1 “Reset Module”  

    Clear C-RAM and DAC interpolation module. It is available only Standby mode.

     

    Page0 0x02 b0  RQPD=1 “Power down mode”

    DAC and Charge pump are forced to standby mode. But digital circuit is kept to operate. There is de-pop time constant takes longer time to restart.  

     

    Page0 0x02 b4 RQST=1 “Standby mode”

    DAC is forced to standby mode. But Charge pump and Digital circuit are kept to operate.

     

    Regards,

    Mochizuki

  • 0 in reply to MK
    TI__Mastermind 46195 points

    Hi kyt and Mochizuki-san,

    For the benefit of the forum, I edited the post above to fix an error. DVDD clears I-RAM, AVDD does not. I also added comments to clarify Mochizuki-san's questions.

    I also added links to two new wiki pages that I hope would address these questions in the future.

    I apologize for any confusion this may have caused.

    Regards,

    J-