The code for this demo is all in https://github.com/dreiss/tiny_sump2_demo .  Feel free to just check it out and skip ahead to the "hardware setup" step.  The following steps will walk through the process of setting up the demo, so you can apply them to your own project.

Create an empty iCEcube2 project for the TinyFPGA BX.  Here's an example: https://github.com/dreiss/tiny_sump2_demo/commit/f346374be9585d6685b93095d2c188df638d99c4

Implement a design that you'd like to debug.  Here's an example: https://github.com/dreiss/tiny_sump2_demo/commit/4e65b2a6fdaa5d979a89089f3bb11d7f3e3f7cbe .  Note the comment in stateful.v.  The design has some internal state that we'd like to observe.

Make sure your FPGA can receive input.  Here's an example implemented as an Arduino sketch: https://github.com/dreiss/tiny_sump2_demo/commit/e5f6077bc92899bb048d97a2410bd87b14001d9a .  Note that input should be generated fairly rapidly to avoid performance problems in the SUMP2 viewer.

Add the unmodified SUMP2 code to your project: https://github.com/dreiss/tiny_sump2_demo/commit/b44aaa4e1f6bd9acc8881914415f8a6c288a2bb9

The TinyFPGA BX runs at 16 MHz by default, so update these parameters: https://github.com/dreiss/tiny_sump2_demo/commit/a7aa9b1ef792d252a55b8bb7fc01e95469b2e2c4

The original SUMP2 code has a top module that includes both internal wiring and external connections.  Encapsulate the internal parts into a reusable module: https://github.com/dreiss/tiny_sump2_demo/commit/6e28a942095cf98aa77c2cadb6ee6d3b6625115e

We need to hook the logic analyzer up to our clock, external serial lines, and any 16 data wires that we want to observe.  Note that the "dot" notation used to capture "st.state" is not supported by Yosys 0.8, so we can't use the Open Source IceStorm toolchain.  See task https://github.com/YosysHQ/yosys/issues/647

First, download the unmodified tools: https://github.com/dreiss/tiny_sump2_demo/commit/52c360c70c2ab0f97055d000e936cc4358a8aaa8

Fix Python 3 compatibility in error handling: https://github.com/dreiss/tiny_sump2_demo/commit/3dc05dd83aa38308e3411e6cc601db00fb71b10c

Fix compatibility with Linux: https://github.com/dreiss/tiny_sump2_demo/commit/913a3751182bab2649d68dd9a32e76e0676e9e29

Fix compatibility with non-FTDI serial cables and our lower serial speed: https://github.com/dreiss/tiny_sump2_demo/commit/cb3f0dbe635d9351ff0b808db2ec26012e6a58f5

Install the Arduino sketch on your 3.3V Arduino.  Install the design on your TinyFPGA.  Wire them together according to the comment in the sketch.  Plug LED anodes into data pins 4,,6,8,10 on the TinyFPGA.  If you have LEDs with integrated resistors, you can plug the cathodes directly into pins 5,7,9,11.  Plug the 3.3V serial cable in to data pins 1 (TX from computer) and 2 (RX to computer).  The LEDs should blink rapidly.  Here's a picture.