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Forum Post: DM814x video DAC power-down

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We're attempting to ensure the power-down of unused video DACs on our DM814x-based design when switching between CVBS and S-Video output modes.  According to the DM816x HDVPSS User's Guide that we've obtained (SPRUHH4), this should be bits 27:24 in SD_VENC_dacsel @ 0x48105F50.

Although we don't have HDVPSS documentation specific to the DM814x, the HDVPSS-01.00.01.37-patched code provided with DVRRDK-03.00.01.03 seems to indicate that the above bits are valid on the DM814x also (ref. VpsHal_sdvencSetOutput() and sdVencDacConfig() in packages/ti/psp/vps/hal/src/vpshal_sdvenc.c), and that the functionality we're testing for should already be present in the HDVPSS drivers.

Can someone at TI please confirm the following:

  • Are these the intended bits in a DM814x to enable / disable individual DAC outputs?
  • Have these bits been verified as operational in the DM814x (i.e. the DACs are not otherwise hardwired "on")?
  • There's no reason that manually "poking" values into SD_VENC_dacsel (i.e. via devmem2) shouldn't result in the immediate enabling / disabling of the associated DACs for testing purposes?

Thanks!

-Cory


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