my_hdmi_device

my_hdmi_device is an implementation inspired by the FPGA4Fun tutorials, ULX3S DVI (vga2dvi) examples, and Larry’s HDMI BlackIceMX example. I learned by reading the code, although I didn’t fully understand everything at first. That’s why I rewrote the TMDS encoder directly from the DVI standard (Page 29) — without any problems. This helped me understand TMDS encoding, why we use LVDS, the challenges involved, and how 8b/10b encoding fits into the bigger picture.

The idea of shifting and using a faster clock appears in all implementations I studied. I also learned about DDR and SDR transmission. 🙂 For iCE40, I learned from MyStorm and Larry’s HDMI example code. The VGA “balls and stars” demo technique I picked up from Steven Hugg’s Designing Video Game Hardware in Verilog.

I borrowed parts of the VGA timing calculation from the ULX3S example code, because usually these values are just shown as fixed tables. I wrote everything from scratch over the Christmas holidays, using the HDMI PMOD from Luke Wren (a gift from UltraEmbedded).

I want to share what I figured out and got working. Maybe this code can be a new base for other projects. Just use tmds_encoder, hdmi_device.h, and learn from the top module — then you’ll be ready for your next project.

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Supported Boards

This code runs on BlackIceMX and ULX3S-85F (you can adjust the Makefile to generate fewer “balls” if needed). I don’t want to go too deep into the details, because I want to explore many FPGA designs in the future. But everything starts with the basics.

I used this PMOD for iCE40-based FPGAs: 👉 https://github.com/Wren6991/DVI-PMOD

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TODO

• HDMI audio (island mode)

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Build Instructions

ULX3S: make prog

BlackIceMX: make -f Makefile.blackicemx prog

Icoboard: make -f Makefile.icoboard prog

iCEstick: cd icestick__hack make prog

Arty7: make -f Makefile.arty7 prog ⚠️ Currently not working. Use Vivado instead. Enable with: define ARTY7 DDR/SDR both work.

Colorlight i5: make -f Makefile.colorlighti5 prog

Tang Nano 4K: define NANO_4K Open project file: nano4k/my_hdmi_nano/my_hdmi_nano.gprj

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Have fun!

Hirosh