15 lines
746 B
Markdown
15 lines
746 B
Markdown
# WS2812 driver gateware for blinkenwall v3
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At 100 FPS, a single strand of WS2812 can only be just over 300 LEDs long:
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```
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MAX_LENGTH = (1 / FPS - RESET_TIME) / BIT_TIME / BITS_PER_PIXEL
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318 = (1 / 100 - 50e-6) / 1.3e-6 / 24
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```
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Because blinkenwall v3 has `64 * 96 = 6144` pixels, driving it at 100 FPS requires at least
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`6144 / 318 = 20` parallel drivers. For simplicity, the wall is devided into 24 strands of
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256 LEDs. Unfortunately, most microcontrollers have at most a couple WS2812-capable interfaces
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(typically SPI), so this would require coordinating several microcontrollers in parallel. A
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much more integrated solution is to instantiate as many WS2812 drivers as desired in an FPGA,
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then point the entire video firehose at the FPGA.
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