AnsweredAssumed Answered

ADV7844/42 close caption pass through

Question asked by Elle on Apr 2, 2012
Latest reply on Apr 3, 2012 by Elle


I am using ADV7844/42 chip in our design and I would like to pass through the closed captioning data that can be decoded by our chip, I have used this settings on top of our CVBS (NTSC) script to enable the pass through from one of the threads here.

[SDPIOMap][0xB0][7] = 0 (SDP_VBLANK_EN)

[SDPIOMap][0xB0][6] = 0 (SDP_HBLANK_EN)

[SDPMap][0x18][7] = 0 (SDP_BLANK_C_VBI)

but it looks that the CC data instead of line 21 is being send on line 17!!

I have confirmed our end with testing the same back end with ADV7403 and Trident chip and they look to work fine, but for ADV7844/42 front end we have to modify the driver.

I have checked all the registers related to the 656 data and all of them have their default value, would you please let me know if this is a known issue and if there is any fix for it.