From 251d8754dc13d1edb8ed13836365323fb9ce6473 Mon Sep 17 00:00:00 2001 From: David Phillips Date: Mon, 25 Oct 2021 21:11:47 +1300 Subject: Add README.md --- README.md | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 README.md diff --git a/README.md b/README.md new file mode 100644 index 0000000..b147f10 --- /dev/null +++ b/README.md @@ -0,0 +1,17 @@ +# Obligatory blinky for the 5A-75E + +This quick-and-dirty design blinks the green user LED on the Colorlight 5A-75E +at 1 Hz with a 50% duty. It divides the 25 MHz crystal oscillator input to the +FPGA down with a counter to achieve this. + +## Notes + +I've seen one of the HC245s decide to oscillate if you flash this bitstream +after letting the factory design start. It tried to draw my current limit of +500 mA, and would presumably draw more if allowed. It's probably due to this +design leaving unused I/Os in high-Z. It seems not to be able to get itself +into the state when I set a lower current limit and/or a lower voltage on the +board's main input, such as 300 mA and/or 3.3 V. + +Another workaround is not to load the factory design boot up. + -- cgit v1.1