Frequently Asked Question
How to configure the ADV202/212 for 4Kx4K input images
If the image data is monochrome, It is required to tile the input into 16 1K x 1K tiles before compression and send them sequentially to the ADV202/212. Considering the HDATA data input rate limitations, this would allow an input rate of approx. 40 images/sec.
For color images the images would have to be tiled further to stay under the maximum image size limit of 1.048 Msamples/image.
A recommended configuration for this application is to use HIPI mode.
For a general overview of HIPI mode refer to: ADV202 HIPImode Still Image Application
This mode expects the image data to be in pixel raw format with no timing information associated with the pixel data. Pixel data can be monochrome or YCbCr 4:2:2 data. How the pixel data should be aligned on the 32-bit HDATA bus is covered in the ADV202/212 User's Guide.
Apart from the direct register configuration, the following indirect register must be configured for this particular configuration:
Timing specification for DREQ/DACK Burst Mode can be found in the ADV202/212 datasheet.
EDMOD registers should stay disabled while they are configured and should be enabled before clearing EIRQFLG 0x0400 to start the program. Refer to the ADV202/212 Programming Guide for recommended programming sequence.
Recommended Encode parameter settings:
Encode and decode parameters PREC, UNI, PICFG are ignored in HIPI mode. They must be set with the indirect register accesses mentioned above.
Recommended Decode parameter settings:
Once the program is started DMA channel 0 will assert DREQ0/ requesting uncompressed data to be input into the Pixel FIFO. As soon as compressed data is available DREQ1/ will assert. This generally happens after 1 complete image has been input.
For most robust data transfer, it is recommended to service the DREQ/s in a round-robin fashion once both are asserting. This means service burst from DREQ0/, then service burst from DREQ1/.
Images can be input continuously. It is not required to read out all the compressed image data for one image before the next image can be input. Individual images are identified in the ADV202/212 generated header with the image index number. The ADV202/212 header will be inserted at the start of each compressed image.
The ADV202/212 will not merge the sixteen tiles into a complete image. This must be done externally.