fpgalafw

This is a preliminary design

fpgalafw is a proposal for a project to implement a universal logic analyser firmware for use as a firmware for commercial logic analysers that we wish to support, on FPGA development boards and for use as an in-circuit, or even in-FPGA debugging tool.

Previous Projects

There are various pre-existing open source firmware projects that can be drawn upon:

• 2004 - eebit
• 2006 - SUMP (written in VHDL)
• 2008 - openVeriFLA
• 2009 - miniLA
• 2009 - LeKernel's Logic Analyser
• 2010 - BitHound (Derived from SUMP but with Ethernet interface)
• 2011 - OpenBench Logic Sniffer (Derived from SUMP, ported to Verilog)
  • Demon Core Verilog Source Code SVN

Benefits

• Would simplify the implementation of libsigrok.
  • Reduced repetition.
  • Advanced triggering becomes hard when every manufacturer has a different trigger model. We can implement one to cover a variety of devices.
• Unlock previously unsupported device features. If a feature is added to one LA, it is added to all.
• Would enable support for more analysers such as the RockyLogic Ant8, the RockyLogic Ant18e, the ChronoVu LA8 etc.

Components

fpgalafw will not work as a monolithic single firmware. Rather it is a library/framework of components that can be assembled together depending on the capabilities of the device, and the mode of operation.

Host Interface Cypress FX2 FTDI FT245 USB Fifo RS232 (SUMP) Ethernet USB-MCU JTAG - for ChipScope-like in-circuit use cases. PCIe? Parallel Port? Cypress FX3?

Storage Internal Block-RAM (BRAM) External DRAM External SDRAM (DDR2, DDR3) Burst RAM Internal Soft-RAM? (Shift Registers) Streaming Pass-through

Data Packer N-probes to M-data Lines Muxer RLE Encoder RLE + Golomb/Huffman/... Encoder?

Indicator LEDs None Tri-colour Multiple LEDs

Operating Modes Storage Sampling Asynchronous Mode Externally Clocked Synchronous (State Analysis) Mode Continuous Sampling Pulse Counter Time-to-digital Conversion Signal Generation

Triggering External Simple (Edge/Level) Time Delayed Advanced Triggers (the Demon Core replicates the behaviour of the HP16550)

Project Folder Structure

Proposed project folder structure...

• /
  • README
  • NEWS
  • Makefile
  • /boards
    • /openbench-logic-sniffer
    • /nexys2
    • /papilio ...
  • /rtl
    • /verilog
      • /host-interface
        • /cypress-fx2
          • /software
          • /firmware
        • /sump
          • /firmware
          • ....
      • /storage
        • /ddr2
          • /firmware
        • /bram
          • /firmware
  • /tools
    • # Scripts etc in here
  • /sw
    • # Embedded sofware here

Firmware Packaging

Each device class will be given a firmware package that the driver can load. This package will be ZIP-file containing multiple firmware .bit files for the different permutations of modes and options that can be selected on this device. It is undesirable to have a single universal hardware file for each device, because multiple features will compete for use the limited number of logic units and internal storage.

The firmware package will contain a text index file that indicates the capabilities of the device, its Bus ID, and a list of the firmware files available.

Firmware Build Environment

The firmware will be built using a GNU Make driven build environment, which will be compatible with Altera, Xilinx, Lattice tools, and FreeHDL etc.

Protocol

We will implement a common command protocol, common among all the host interfaces. (With the possible exception of SUMP if we plan to support that).