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Category: Hardware

We have built a LCD display controller that can accept VGA signal and display the same on a LCD panel of any size. We are using ADV7802BSTZ-150 to digitize the VGA input and Xilinx XC7Z014-2CLG484 Zynq FPGA for digital signal processing and generate the LVDS signal for the LCD panel.

We find that the ADV7802BSTZ-150 does not support the AutoGraphics mode - unlike other chips in the Analog Stable like ADV7604BBCZ-5P. Because of this, we are not able to support non standard VGA signal (For example a VGA signal with Vertical synq frequency of 50 Hz (instead of the standard 56 Hz or 60 Hz). The LCD controller supports all standard VGA resolutions nicely. But we want support for non-standard resolutions.

Is there a work around for this or any way we can make the Autographics mode work on ADV7802BSTZ-150 by assigning one of the 'reserved' modes in the mode support table of ADV7802?

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  • FormerMember
Oct 5, 2023 +1 verified

The ADV7802 can handle graphic formats up to SXGA using the component processor.  PRIM_MODE=0100.  

From the manual found here:

2.5.7 Nonstandard CP PLL Modes of Operation For all nonstandard CP PLL modes, PRIM_MODE and VID_STD must be to set to the nearest available standard to correctly configure the internal parameters of the CP core to decode the specific SD/HD/GR and interlace/progressive standard. Depending on the required pixel clock frequency, the PLL divisor ratio, VCO range, and PLL_QPUMP settings must be set to configure the PLL to generate a stable LLC. Refer to Section 2.5.1 to set the correct PLL divisor ratio. The recommended VCO range and PLL charge pump settings can be set by referring to Table 6 and Equation 1.