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orangecrab_r0.1

README.md

Orange Crab r0.1

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ECP5 DDR3 memory in a Feather form-factor.

Hardware r0.1 is not the latest hrdware version. There are some bugs listed below.

What is it

Project goal: "Make a simple ECP5 breakout board with DDR3L memory". As that was the only design goal I also decide it might be nice to keep the overal size small and make it an adafruit feather compatible dev board.

Hardware Overview

  • Lattice ECP5 25 (With limited support for 45/85 variants)
  • DDR3L Memory upto 1Gbit (64Mbit x16)
  • Micro USB connection
  • Full-speed (12Mbit) USB direct connection to FPGA
  • Battery charger, with charge indicator LED (1-cell: 3.7-4.2V)
  • Reset Button
  • 16Mbit QSPI FLASH Memory (Bitstream + User storage)
  • 4bit MicroSD socket
  • 48MHz Oscillator (Used by USB system)
  • ATSAMD10/11 Co-processor planned mainly for the ADC/DAC
  • Spare 3.3V I/O's broken out onto a 30pin low profile connector
    • 7 diff pairs
    • 1 single ended only

Errata

  1. FLASH footprint only supports devices upto 16Mbit in size, This is enough for a bootloader and user gateware on the 25/45F parts, but not enough for a fully loaded 85F design.
  2. DDR3 traces are quite close, violating the recommended 6mil clearance. Tests appear to indicate this isn't a huge deal on this design.
  3. No firmware was ever written for the SAMD11 co-precessor, so A0-A5 don't do anything.
  4. LED resistor values are not tuned very well, resulting in very bright USB-Present LED.
  5. The button is tied directly to PROGRAMN pin on the FPGA, this means pressing the button resets the device. (Which is used to toggle between user/bootloader gateware)

Back Photo

Licence

  • Hardware in this repository is licenced under CERN OHL v1.2
  • Gateware/Software/Firmware in this repository is licenced under MIT unless otherise indicated

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