Designing a HDMI capable Board with F1C100s Processor - Seeking Input

[ShadowNomad]

Hey there!

there are a variety of boards based on the F1C100s/F1C200s processor, and I am currently working on designing my own. The datasheet shows that the processor offers several display output options, including a Parallel RGB interface with resolutions up to 1280x720@60fps.



However, I don't plan to connect a display directly, but am considering integrating an alternate output. The F1C200s does offer a TV composite output that I could theoretically use, but so far I haven't seen anyone actually use this feature in their board design. Also, I'm unsure if Linux supports this output as a display, especially given Allwinner's lack of documentation. In addition, the quality of a composite signal is not comparable to a clear digital signal, and three jacks (2 for stereo audio and 1 for video + an amplifier circuit for the audio) takes up a lot of space on the board.

So I am considering integrating HDMI with an HDMI transmitter IC like the Sil9022. However, I wonder if this would actually work. A first look at the datasheet of the Sil9022 shows that it supports a 1280x720@60fps signal as input.



I2S audio is also supported by both ICs. However, the F1C100s is not very powerful and does not even have a GPU let alone an FPU. In addition, I'm also interested to know if any public schematics based on the Sil9022 exist, as I personally haven't found any.

I am aware that my board will probably not be any more compact than a Raspberry Pi Zero and will definitely offer fewer features (and thus be pretty useless). Still, the idea of having a chip output HDMI without a dedicated GPU fascinates me. I think it could be an exciting design challenge.

What are your thoughts on this? Can anyone help me with some information?

Many thanks in advance!

[DavidAlfa]

Have you seen the SSD210 chip? Much more powerful and still very cheap.
https://www.cnx-software.com/2021/03/19/sigmastar-ssd210-tiny-dual-core-arm-cortex-a7-soc-64mb-ram-rgb-display/

[ShadowNomad]

The SSD210 is definitely interesting. However, I have already decided to go with the F1C200s chip in my current design and the SSD210 is also definitely harder to find online. For future projects though, I will keep an eye on the SSD210 as it is promising. Thanks for the tip!

[DavidAlfa]

Well in that case leave composite signal as last resort,. composite quality is pretty bad.

You might be able to do something with the lcd output:

https://www.eevblog.com/forum/beginners/capturing-video-from-lcd-interface/msg5059381/#msg5059381

[ShadowNomad]

I have looked at the TFP410 IC you linked before and it seems to be much better documented than the Sil9022 (and a bit simpler overall). However, it doesn't support audio, which is different with the Sil9022 HDMI transmitter I was considering.

[ShadowNomad]

Alright, I at least managed to find some reference designs in the last days for the Sil9022 IC.
https://www.ti.com/lit/df/sprr295/sprr295.pdf?ts=1696183589877
https://web.archive.org/web/20220121021043/https://www.st.com/content/ccc/resource/technical/layouts_and_diagrams/schematic_pack/group0/36/8e/ea/7a/ca/ca/4b/e4/mb1272-dk2-c01_schematic/files/MB1272-DK2-C01_Schematic.pdf/jcr:content/translations/en.MB1272-DK2-C01_Schematic.pdf
Very interesting.