fpga logic analyzer
Due to the impracticality of using DDL's LA(logic analyzer) and the difficulty I encountered using the LA's interface, I decided to implement an LA on my own FPGA. Below are some prerequisites about for such an approach.
- FPGA has 3.3V logic levels
- Proficiency in VHDL/Verilog
- Proficiency with Python or some frontend language
- Proficiency with bash
I found a Logic Analyzer project by the name of SUMP2 written and maintained by Kevin Hubbard from Washington, USA. After a few emails with Kevin Hubbard. I was able to get the RTL LA backend on my HX8k FPGA and the Python frontend working. I document this process below.
Python Frontend Viewer¶
The [repository here] contains the RTL modified Python frontend as described below. There you will find installation instructions and configuration specifics for running SUMP2 on modern Macs. Here are a couple notes about changes I made.
Added "Darwin" to supported OS system - leaving system call behavior unchanged as MacOS terminal calls rarely deviate from those of Linux
if self.os_sys != "Linux" and self.os_sys != "Darwin":
And again on lines 2028, 2039, 2050, and 2178
if ( self.os_sys == "Linux" or self.os_sys == "Darwin"):
I also changed the default font for MacOS system to make it more readable - pygame doesn't seem to play nice with non-retina display
1 2 3 4
if(self.os_sys == "Darwin"): font_height = int( font_height, 20 ); # Conv String to Int else: font_height = int( font_height, 10 ); # Conv String to Int
Verilog Backend and Sump2 Protocol¶
It was necessary to make a number of modifications to the verilog to get it working with the Lattice HX8K. I originally used the proprietary ICEcube2 software to synthesize, time, layout, and verify my designs, but I quickly switched to the IceStorm toolchain by Clifford Wolf as it is much faster and reliable.
The sump2 verilog was designed for the Lattice HX1K icesticick board, so I first went through the HX1K's schematics while browsing through top.v. I had to hook up the FTDI ports to their respective pins on the HX8k. To do this, I referenced the HX8K schematics. I also assigned the status LEDs to their respective pins.