See it in action!
The VGA timing is based directly on VEGA 640x480 @ 75 Hz.
Using a tile-based beam-racing triangle render has always seemed like a good way to deal with the lack of a framebuffer. Tiny Tapeout gave me an opportunity to play with it. However as this effort is pretty much defined by a mad-scramble to get SOMETHING done for Nov 4th everything is a consequence of that, so the design is very simple and not very ambitious.
Every frame the 640x480 VGA matrix is scanned, advancing the state of the intersecting lines of the three triangles. If the (x,y) coordinate of the "beam" lines on the positive side of each line, the beam is inside the triangle. Among the visible triangles, the highest priority triangle sets the color, else we default to a grey color. Twelve dots are also marked, to make it easier to read the clock.
The algorithm might be easily understood by examining the software
model in Rust, in the sw directory.
The main "UI" is two buttons to advance hour and minutes respectively. The least significant two bits selects which outputs are routed to the bidirectional port (frame number, seconds * 4 + hz-strobe * 2 + vs-strobe, minute * 4, hour * 4).
TinyTapeout is an educational project that aims to make it easier and cheaper than ever to get your digital designs manufactured on a real chip.
To learn more and get started, visit https://tinytapeout.com.
Edit the info.yaml and change the wokwi_id to the ID of your Wokwi project. You can find the ID in the URL of your project, it's the big number after wokwi.com/projects/.
The GitHub action will automatically fetch the digital netlist from Wokwi and build the ASIC files.
Edit the info.yaml and uncomment the source_files and top_module properties, and change the value of language to "Verilog". Add your Verilog files to the src folder, and list them in the source_files property.
The GitHub action will automatically build the ASIC files using OpenLane.
- Submit your design to the next shuttle on the website. The closing date is November 4th.
- Edit this README and explain your design, how it works, and how to test it.
- Share your GDS on your social network of choice, tagging it #tinytapeout and linking Matt's profile:
- LinkedIn #tinytapeout matt-venn
- Mastodon #tinytapeout @matthewvenn
- Twitter #tinytapeout @matthewvenn