64 lines
2.7 KiB
Markdown
64 lines
2.7 KiB
Markdown
# Pico Ice Video
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This repository displays a video signal from the Pico Ice FPGA on the
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desktop computer, over USB, using the USB Video Device Class (UVC).
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You can then take screenshots, record the video, or use it as a demo
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during a Zoom call.
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Here is the [FPGA
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interface](https://git.shylie.info/shylie/pico-ice-video/src/branch/main/ice/mandelbrot/source/impl_1/top.sv). There
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is a start wire, really that is the vertical sync signal. There are 8
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bits of data that get sent to the RP2040. The RP2040 reads the data
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using PIO, writes the data to the inactive frame buffer using direct
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memory access. Meanwhile the TinyUSB library is writing uncompressed
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data to the desktop over USB using the active frame buffer. The
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RP2040 sysclk runs at120 MHz, the clkdiv for the pio is 2.5 and the
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FPGA runs at 48Mhz. The image size is 320 * 180. The next version of
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the Pico-Ice will have the RP2350 Chip which will also support a
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higher resolution HDMI output.
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This software is based on the [Tiny video USB Capture example](
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https://github.com/hathach/tinyusb/tree/master/examples/device/video_capture).
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UVC does not need to be fully synchronous: there is no timing to
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keep-up with: if you send the frame sometimes slow sometimes fast, it
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is fine. In particular if using BULK (throw data in like it's a
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truck) endpoint rather than ISOCHRONOUS (always same time
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interval...)
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## Contact
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If you have questions, first please search the Pico Ice discord
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server, and then ask. This is a private repository, to make
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contributions, please post your branch somewhere and notify the author
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@shylie on the Pico Ice Discord server.
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## INSTALLATION
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To install it on linux , [put the Pico-Ice into install mode](
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https://pico-ice.tinyvision.ai/md_programming_the_mcu.html )
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Using the command
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picocom) --baud 1200 /dev/ttyACM0
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Then drag the executable onto the RP2040 drive on the desktop.
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## TO DO
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**Implement compression**. There are lower complexity compression
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techniques,PEG-XS seems to be one of the newer standards thats meant
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for low latency and reasonable compression. This may be doable with
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the RPi in FW. Doubt MJPG is possible for larger frames as that
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requires multiple frames to be in memory.
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**Free UP SPI and UART pins** The interface requires 9 pins. There
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are 8 RP2040<->FPGA pins, so one of the spi pins is also used. One
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could solder a pin between the FPGA and RP2040 and preserve the SPI
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bus. Better yet, solder 3 pins and preserve both the SPI bus, and
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the default part.
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## Special Thanks
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Christopher Lozinski (@clozinski) - wrote this README file. Thank you!
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josuah (@josuah.demangeon) - helped answer questions during the development of this project
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venkat_tv (@venkat_tv) - developed the pico-ice hardware |